Shore Keeper

{7}{U}, {T}, Sacrifice Shore Keeper: Draw three cards.

Cryptic Trilobite

Cryptic Trilobite enters with X +1/+1 counters on it.
Remove a +1/+1 counter from Cryptic Trilobite: Add {C}{C}. Spend this mana only to activate abilities.
{1}, {T}: Put a +1/+1 counter on Cryptic Trilobite.

Electryte

Whenever Electryte deals combat damage to defending player, it deals damage equal to its power to each blocking creature.

Scuttling Sliver

Sliver creatures you control have "{2}: Untap this creature."