Blight Mound

Attacking Pests you control get +1/+0 and have menace.
Whenever a nontoken creature you control dies, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."

Search for Blex

Look at the top five cards of your library. You may put any number of them into your hand and the rest into your graveyard. You lose 3 life for each card you put into your hand this way.

Blex, Vexing Pest

Other Pests, Bats, Insects, Snakes, and Spiders you control get +1/+1.
When Blex dies, you gain 4 life.

Blex, Vexing Pest // Search for Blex

Blech, Loafing Pest

Whenever you gain life, put a +1/+1 counter on each Pest, Bat, Insect, Snake, and Spider you control.

Feral Appetite

Attacking Pests you control get +1/+0 and have deathtouch.
{1}{G}: Exile target card from a graveyard. If a creature card is exiled this way, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."

Turn Stones

For each opponent, you create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."

Eccentric Pestfinder

Trample
At the beginning of each end step, if you gained life this turn, this creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)