Crystalline Crawler [Commander Anthology Volume II] BT6-036 you may search your library

you may search your library for up to two basic land cards

Set: Unstable Type: Creature — Goblin Rigger Rarity: Rare Cost: {3}{R} Other Riggers you control get +1/+0 and have haste

Set: Amonkhet Type: Creature — Bird Rarity: Uncommon Cost: {3}{B} This spell costs {3} less to cast if a creature died this turn

Then investigate

Crystalline Crawler [Commander Anthology Volume II] BT6-036 you may search your librarySet: Commander Anthology Volume II Type: Artifact Creature Construct Rarity: Rare Cost: {4} Converge Crystalline Crawler enters the battlefield with a +1 +1 counter on it for each color of mana spent to cast it. Remove a +1 +1 counter from Crystalline Crawler: Add one mana of any color. {T}: Put a +1 +1 counter on Crystalline Crawler.