Bello, Bard of the Brambles

During your turn, each non-Equipment artifact and non-Aura enchantment you control with mana value 4 or greater is a 4/4 Elemental creature in addition to its other types and has indestructible, haste, and "Whenever this creature deals combat damage to a player, draw a card."

Fetch Quest

Mill seven cards. Then put a creature, enchantment, or land card from among the milled cards onto the battlefield.

Bramble Familiar

{T}: Add {G}.
{1}{G}, {T}, Discard a card: Return this creature to its owner's hand.

Bramble Familiar // Fetch Quest

Teapot Slinger

Menace
Whenever you expend 4, this creature deals 2 damage to each opponent. (You expend 4 as you spend your fourth total mana to cast spells during a turn.)

Trailtracker Scout

{T}: Add one mana of any color.
Whenever you expend 8, return up to one target permanent card from your graveyard to your hand. (You expend 8 as you spend your eighth total mana to cast spells during a turn.)

Muerra, Trash Tactician

At the beginning of your first main phase, add {R} or {G} for each Raccoon you control.
Whenever you expend 4, you gain 3 life. (You expend 4 as you spend your fourth total mana to cast spells during a turn.)
Whenever you expend 8, exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Bark-Knuckle Boxer

Whenever you expend 4, this creature gains indestructible until end of turn. (You expend 4 as you spend your fourth total mana to cast spells during a turn.)

Prosperous Bandit

Offspring {1} (You may pay an additional {1} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
First strike
Whenever this creature deals combat damage to a player, create that many tapped Treasure tokens.

Keen-Eyed Curator

As long as there are four or more card types among cards exiled with this creature, it gets +4/+4 and has trample.
{1}: Exile target card from a graveyard.

Wandertale Mentor

Whenever you expend 4, put a +1/+1 counter on this creature. (You expend 4 as you spend your fourth total mana to cast spells during a turn.)
{T}: Add {R} or {G}.

Brazen Collector

First strike
Whenever this creature attacks, add {R}. Until end of turn, you don't lose this mana as steps and phases end.

Coati Scavenger

Descend 4 — When this creature enters, if there are four or more permanent cards in your graveyard, return target permanent card from your graveyard to your hand.

Byway Barterer

Menace
Whenever you expend 4, you may discard your hand. If you do, draw two cards. (You expend 4 as you spend your fourth total mana to cast spells during a turn.)