Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Blightsteel Colossus

Trample, infect, indestructible
If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.

Darksteel Citadel

Jhoira, Ageless Innovator

{T}: Put two ingenuity counters on Jhoira, Ageless Innovator, then you may put an artifact card with mana value X or less from your hand onto the battlefield, where X is the number of ingenuity counters on Jhoira.

Darksteel Colossus

Trample, indestructible
If Darksteel Colossus would be put into a graveyard from anywhere, reveal Darksteel Colossus and shuffle it into its owner's library instead.

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Darksteel Forge

Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)