Bog Serpent

Bog Serpent can't attack unless defending player controls a Swamp.
When you control no Swamps, sacrifice Bog Serpent.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.