Sakiko, Mother of Summer

Whenever a creature you control deals combat damage to a player, add that much {G}. Until end of turn, you don't lose this mana as steps and phases end.

Rhonas's Monument

Green creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature you control gets +2/+2 and gains trample until end of turn.

Forest

Emerald Medallion

Green spells you cast cost {1} less to cast.

Ant Queen

{1}{G}: Create a 1/1 green Insect creature token.