Omnath, Locus of Mana

You don't lose unspent green mana as steps and phases end.
Omnath, Locus of Mana gets +1/+1 for each unspent green mana you have.

Curse of Bounty

Enchant player
Whenever enchanted player is attacked, untap all nonland permanents you control. Each opponent attacking that player untaps all nonland permanents they control.

Wilderness Reclamation

At the beginning of your end step, untap all lands you control.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Forest

Vedalken Orrery

You may cast spells as though they had flash.