Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Nature's Claim

Destroy target artifact or enchantment. Its controller gains 4 life.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Journey to the Oracle

You may put any number of land cards from your hand onto the battlefield. Then if you control eight or more lands, you may discard a card. If you do, return Journey to the Oracle to its owner's hand.

Jadzi, Oracle of Arcavios

Discard a card: Return Jadzi, Oracle of Arcavios to its owner's hand.
Magecraft — Whenever you cast or copy an instant or sorcery spell, reveal the top card of your library. If it's a nonland card, you may cast it by paying {1} rather than paying its mana cost. If it's a land card, put it onto the battlefield.

Jadzi, Oracle of Arcavios // Journey to the Oracle

Dark Depths

Dark Depths enters with ten ice counters on it.
{3}: Remove an ice counter from Dark Depths.
When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Dreamroot Cascade

Dreamroot Cascade enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Hinterland Harbor

Hinterland Harbor enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Yorvo, Lord of Garenbrig

Yorvo, Lord of Garenbrig enters with four +1/+1 counters on it.
Whenever another green creature you control enters, put a +1/+1 counter on Yorvo. Then if that creature's power is greater than Yorvo's power, put another +1/+1 counter on Yorvo.

Forest

Lonely Sandbar

Lonely Sandbar enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Guardian Augmenter

Flash
Commander creatures you control get +2/+2.
Commanders you control have hexproof.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Simic Guildgate

Simic Guildgate enters tapped.
{T}: Add {G} or {U}.

Tangled Islet

({T}: Add {G} or {U}.)
Tangled Islet enters tapped.

Vivid Grove

Vivid Grove enters tapped with two charge counters on it.
{T}: Add {G}.
{T}, Remove a charge counter from Vivid Grove: Add one mana of any color.

Venser, Shaper Savant

Flash
When Venser, Shaper Savant enters, return target spell or permanent to its owner's hand.

Lumbering Falls

Lumbering Falls enters tapped.
{T}: Add {G} or {U}.
{2}{G}{U}: Lumbering Falls becomes a 3/3 green and blue Elemental creature with hexproof until end of turn. It's still a land.

Tidechannel Pathway

Barkchannel Pathway

Barkchannel Pathway // Tidechannel Pathway

Reshape the Earth

Search your library for up to ten land cards, put them onto the battlefield tapped, then shuffle.

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Quandrix Campus

Quandrix Campus enters tapped.
{T}: Add {G} or {U}.
{4}, {T}: Scry 1.

Bloodline Shaman

{T}: Choose a creature type. Reveal the top card of your library. If that card is a creature card of the chosen type, put it into your hand. Otherwise, put it into your graveyard.

Uro, Titan of Nature's Wrath

When Uro enters, sacrifice it unless it escaped.
Whenever Uro enters or attacks, you gain 3 life and draw a card, then you may put a land card from your hand onto the battlefield.
Escape—{G}{G}{U}{U}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Titania's Command

Choose two —
• Exile target player's graveyard. You gain 1 life for each card exiled this way.
• Search your library for up to two land cards, put them onto the battlefield tapped, then shuffle.
• Create two 2/2 green Bear creature tokens.
• Put two +1/+1 counters on each creature you control.

Alchemist's Refuge

{T}: Add {C}.
{G}{U}, {T}: You may cast spells this turn as though they had flash.

Seasons Past

Return any number of cards with different mana values from your graveyard to your hand. Put Seasons Past on the bottom of its owner's library.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Joraga Visionary

When Joraga Visionary enters, draw a card.

Thryx, the Sudden Storm

Flash
Flying
Spells you cast with mana value 5 or greater cost {1} less to cast and can't be countered.

Negate

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Awoken Horror

When this creature transforms into Awoken Horror, return all non-Horror creatures to their owners' hands.

Thing in the Ice

Defender
Thing in the Ice enters with four ice counters on it.
Whenever you cast an instant or sorcery spell, remove an ice counter from Thing in the Ice. Then if it has no ice counters on it, transform it.

Thing in the Ice // Awoken Horror

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Waterlogged Grove

{T}, Pay 1 life: Add {G} or {U}.
{1}, {T}, Sacrifice Waterlogged Grove: Draw a card.

Chatterstorm

Create a 1/1 green Squirrel creature token.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Serum Visions

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.

Euroakus

When Euroakus enters, create a number of 1/1 blue Human Wizard creature tokens equal to the number of differently named lands you control.
{4}{G}{U}: Draw a card for each Wizard you control. They each get +1/+1 until end of turn for each card in your hand.

Ezuri's Predation

For each creature your opponents control, create a 4/4 green Phyrexian Beast creature token. Each of those tokens fights a different one of those creatures.

Tanglepool Bridge

Tanglepool Bridge enters tapped.
Indestructible
{T}: Add {G} or {U}.

Biophagus

Genomic Enhancement — {T}: Add one mana of any color. If this mana is spent to cast a creature spell, that creature enters with an additional +1/+1 counter on it.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Guildless Commons

Guildless Commons enters tapped.
When Guildless Commons enters, return a land you control to its owner's hand.
{T}: Add {C}{C}.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Thornwood Falls

Thornwood Falls enters tapped.
When Thornwood Falls enters, you gain 1 life.
{T}: Add {G} or {U}.

Ivy Seer

{2}{G}, {T}: Reveal any number of green cards in your hand. Target creature gets +X/+X until end of turn, where X is the number of cards revealed this way.

Vineglimmer Snarl

As Vineglimmer Snarl enters, you may reveal a Forest or Island card from your hand. If you don't, Vineglimmer Snarl enters tapped.
{T}: Add {G} or {U}.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Ondu Giant

When Ondu Giant enters, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

The Magic Mirror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
You have no maximum hand size.
At the beginning of your upkeep, put a knowledge counter on The Magic Mirror, then draw a card for each knowledge counter on The Magic Mirror.

Vedalken Aethermage

Flash (You may cast this spell any time you could cast an instant.)
When Vedalken Aethermage enters, return target Sliver to its owner's hand.
Wizardcycling {3} ({3}, Discard this card: Search your library for a Wizard card, reveal it, put it into your hand, then shuffle.)

Sea Gate Oracle

When Sea Gate Oracle enters, look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Tranquil Thicket

Tranquil Thicket enters tapped.
{T}: Add {G}.
Cycling {G} ({G}, Discard this card: Draw a card.)

Arcane Proxy

Prototype {1}{U}{U} — 2/1 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
When Arcane Proxy enters, if you cast it, exile target instant or sorcery card with mana value less than or equal to Arcane Proxy's power from your graveyard. Copy that card. You may cast the copy without paying its mana cost.

Skyshroud Forest

Skyshroud Forest enters tapped.
{T}: Add {C}.
{T}: Add {G} or {U}. Skyshroud Forest deals 1 damage to you.

Mnemonic Deluge

Exile target instant or sorcery card from a graveyard. Copy that card three times. You may cast the copies without paying their mana costs. Exile Mnemonic Deluge.

Cyclone Summoner

When Cyclone Summoner enters, if you cast it from your hand, return all permanents to their owners' hands except for Giants, Wizards, and lands.

Gale, Waterdeep Prodigy

Whenever you cast an instant or sorcery spell from your hand, you may cast up to one target card of the other type from your graveyard. If a spell cast from your graveyard this way would be put into your graveyard, exile it instead.
Choose a Background (You can have a Background as a second commander.)

Elvish Hydromancer

Kicker {3}{U} (You may pay an additional {3}{U} as you cast this spell.)
When Elvish Hydromancer enters, if it was kicked, create a token that's a copy of target creature you control.

Snow-Covered Forest

Umara Skyfalls

Umara Skyfalls enters tapped.
{T}: Add {U}.

Umara Wizard

Whenever you cast an instant, sorcery, or Wizard spell, Umara Wizard gains flying until end of turn.

Umara Wizard // Umara Skyfalls

Snow-Covered Island

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Magus of the Order

{G}, {T}, Sacrifice Magus of the Order and another green creature: Search your library for a green creature card, put it onto the battlefield, then shuffle.

Towering Titan

Towering Titan enters with X +1/+1 counters on it, where X is the total toughness of other creatures you control.
Sacrifice a creature with defender: All creatures gain trample until end of turn.

Magus of the Library

{T}: Add {C}.
{T}: Draw a card. Activate only if you have exactly seven cards in hand.

Weather the Storm

You gain 3 life.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Wizard's Retort

This spell costs {1} less to cast if you control a Wizard.
Counter target spell.

Simic Growth Chamber

Simic Growth Chamber enters tapped.
When Simic Growth Chamber enters, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Lier, Disciple of the Drowned

Spells can't be countered.
Each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost.

Lair of the Hydra

If you control two or more other lands, Lair of the Hydra enters tapped.
{T}: Add {G}.
{X}{G}: Until end of turn, Lair of the Hydra becomes an X/X green Hydra creature. It's still a land. X can't be 0.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Regrowth

Return target card from your graveyard to your hand.

Adrix and Nev, Twincasters

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
If one or more tokens would be created under your control, twice that many of those tokens are created instead.

Dryad Arbor

(Dryad Arbor isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G}.")

Primal Wellspring

(Transforms from Primal Amulet.)
{T}: Add one mana of any color. When that mana is spent to cast an instant or sorcery spell, copy that spell and you may choose new targets for the copy.

Primal Amulet

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, put a charge counter on Primal Amulet. Then if there are four or more charge counters on it, you may remove those counters and transform it.

Primal Amulet // Primal Wellspring

Earthshaker Giant

Trample
When Earthshaker Giant enters, other creatures you control get +3/+3 and gain trample until end of turn.

Research Assistant

{3}{U}, {T}: Draw a card, then discard a card.

Field of the Dead

Field of the Dead enters tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

Wizards of Thay

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Instant and sorcery spells you cast cost {1} less to cast.
You may cast sorcery spells as though they had flash.

Temple of Mystery

Temple of Mystery enters tapped.
When Temple of Mystery enters, scry 1.
{T}: Add {G} or {U}.

Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Vivid Creek

Vivid Creek enters tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Island

Novijen, Heart of Progress

{T}: Add {C}.
{G}{U}, {T}: Put a +1/+1 counter on each creature that entered this turn.

Mirari

Whenever you cast an instant or sorcery spell, you may pay {3}. If you do, copy that spell. You may choose new targets for the copy.

Steel Exemplar

Trample
Steel Exemplar enters with two +1/+1 counters on it unless two or more colors of mana were spent to cast it.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.