Flight

Enchant creature
Enchanted creature has flying.

Honey Mammoth

When Honey Mammoth enters, you gain 4 life.

Aggressive Mammoth

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Other creatures you control have trample.

Prized Elephant

Prized Elephant gets +1/+1 as long as you control a Forest.
{G}: Prized Elephant gains trample until end of turn. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Elephant Grass

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Black creatures can't attack you.
Nonblack creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Arcane Flight

Enchant creature
Enchanted creature gets +1/+1 and has flying.

Rogue Elephant

When Rogue Elephant enters, sacrifice it unless you sacrifice a Forest.

Kazandu Valley

Kazandu Valley enters tapped.
{T}: Add {G}.

Kazandu Mammoth

Landfall — Whenever a land you control enters, Kazandu Mammoth gets +2/+2 until end of turn.

Kazandu Mammoth // Kazandu Valley

Rabid Elephant

Whenever Rabid Elephant becomes blocked, it gets +2/+2 until end of turn for each creature blocking it.