And in a format where instant removal is at its worst, you have the power to simply end games on the spot with the four mana combo of Blitzball Shot into post-combat Self-Destruct
Clever Impersonator is excellent any time you have at least an okay board state, but is best used when copying something that will cause a huge amount of ability triggers to go off
Based on the latest market prices tracked on TCG Stacked, Agent Frank Horrigan is worth about $8.62 USD for a regular copy and $11.46 USD for a foil copy
If youre able to keep dumping your hand turn after turn, youll have a steady supply of cards ready for your next turn
Before there was a formal tournament structure or if you were just playing kitchen-table casual Magic you would put as many Plague Rats as you owned in a deck and have at it
Archon of Cruelty seems like one option, and potentially you could be using this with Sneak Attack, dropping out huge creatures then sacrificing them to this to get more creatures