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

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.) Other green creatures you control have intimidate.

{G}: Exile target card from a graveyard. If it was a creature card, put a +1/+1 counter on this creature and you gain 1 life.

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

{T}: Flip a coin. If you win the flip, destroy all nonland permanents.

Destroy target noncreature permanent.

Destroy target artifact or enchantment. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.) Destroy target artifact or enchantment.

This artifact enters tapped. {1}, {T}: Destroy all artifacts, creatures, and enchantments.

Destroy target enchantment. Clash with an opponent. If you win, destroy all enchantments your opponents control. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Put a +1/+1 counter on target creature you control. It gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

This Equipment can be attached only to a creature with toughness 4 or greater. Equipped creature gets +3/+0 and has trample. Equip {3}

Equipped creature has vigilance, trample, and haste. Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

{T}, Discard a card: Up to one target creature can't be blocked this turn. Whenever this artifact becomes untapped, you may pay {2}. If you do, draw a card.

Enchant creature you control When this Aura enters, draw a card. Enchanted creature gets +1/+0 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

For Mirrodin! (When this Equipment enters, create a 2/2 red Rebel creature token, then attach this to it.) Equipped creature gets +4/+4 and has trample. Equip {5}{G}{G}

Equipped creature gets +1/+1 and has vigilance and trample. Equip creature token {1} Equip {3}