Purple Worm

This spell costs {2} less to cast if a creature died this turn.
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Aboroth

Cumulative upkeep—Put a -1/-1 counter on Aboroth. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Aether Searcher

Reveal Aether Searcher as you draft it. Reveal the next card you draft and note its name.
When Aether Searcher enters, you may search your hand and/or library for a card with a name noted as you drafted cards named Aether Searcher. You may cast it without paying its mana cost. If you searched your library this way, shuffle.