Spells can't be countered.
Each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost.

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Whenever an Equipment you control enters, you may draw a card.
Metalcraft — Equipment you control have equip as long as you control three or more artifacts.

Whenever you discard a creature card, create a 2/2 black Zombie creature token.
Whenever you discard a land card, add .
Whenever you discard a noncreature, nonland card, draw a card.

, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Flying
, Sacrifice X lands: Put X +1/+1 counters on this creature.

Trample
Whenever a source deals damage to this creature, that source's controller sacrifices that many permanents of their choice.

, : Exile any number of cards from your hand face down. Put that many cards from the top of your library into your hand. Then look at the exiled cards and put them on top of your library in any order.

: Target creature gets +1/+1 until end of turn.

Whenever a creature you control enters, you may destroy target artifact or enchantment.

Each player secretly chooses a number 0 or greater, then all players reveal those numbers simultaneously and determine the highest and lowest numbers revealed this way. Wheel of Misfortune deals damage equal to the highest number to each player who chose that number. Each player who didn't choose the lowest number discards their hand, then draws seven cards.

When this creature enters, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
, : You may put an Equipment card from your hand onto the battlefield.

(: Add .)

Create X 6/6 green Dinosaur creature tokens with trample named Colossal Dreadmaw.

Flying
If a source you control would deal damage to an opponent or a permanent an opponent controls, it deals double that damage instead.

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
, Sacrifice ten nonland permanents: Each opponent loses 10 life.

: Destroy target enchanted creature.

Search your library and graveyard for five cards and exile the rest. Put the chosen cards on top of your library in any order. You lose half your life, rounded up.

, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Indestructible (Damage and effects that say "destroy" don't destroy this creature.)
If Darksteel Colossus would be put into a graveyard from anywhere, reveal Darksteel Colossus and shuffle it into its owner's library instead.