Viridian Emissary

When Viridian Emissary dies, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Meren of Clan Nel Toth

Whenever another creature you control dies, you get an experience counter.
At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Ashnod's Altar

Wight of the Reliquary

Vigilance
Wight of the Reliquary gets +1/+1 for each creature card in your graveyard.
{T}, Sacrifice another creature: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Wood Elves

When Wood Elves enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Dawntreader Elk

{G}, Sacrifice Dawntreader Elk: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.