Mountain

Mosstodon

{1}: Target creature with power 5 or greater gains trample until end of turn.

Plains

Cartouche of Strength

Enchant creature you control
When this Aura enters, you may have enchanted creature fight target creature an opponent controls. (Each deals damage equal to its power to the other.)
Enchanted creature gets +1/+1 and has trample.

Primal Frenzy

Enchant creature
Enchanted creature has trample.

Horned Helm

Equipped creature gets +1/+1 and has trample.
{G}{G}: Attach this Equipment to target creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Command Tower

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

Duskshell Crawler

When this creature enters, put a +1/+1 counter on target creature.
Each creature you control with a +1/+1 counter on it has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Lightning Spear

Equipped creature gets +1/+0 and has trample.
{2}{R}, Sacrifice this Equipment: It deals 3 damage to any target.
Equip {1}

Elvish Herder

{G}: Target creature gains trample until end of turn.

Armadillo Cloak

Enchant creature
Enchanted creature gets +2/+2 and has trample.
Whenever enchanted creature deals damage, you gain that much life.

Forest

Bestial Fury

Enchant creature
When this Aura enters, draw a card at the beginning of the next turn's upkeep.
Whenever enchanted creature becomes blocked, it gets +4/+0 and gains trample until end of turn.

Messenger's Speed

Enchant creature
Enchanted creature has trample and haste.

Fists of Ironwood

Enchant creature
When this Aura enters, create two 1/1 green Saproling creature tokens.
Enchanted creature has trample.

Etali's Favor

Enchant creature you control
When this Aura enters, discover 3. (Exile cards from the top of your library until you exile a nonland card with mana value 3 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)
Enchanted creature gets +1/+1 and has trample.

Oliphaunt

Trample
Whenever this creature attacks, another target creature you control gets +2/+0 and gains trample until end of turn.
Mountaincycling {1} ({1}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)