one piece card game op05 english OP05-119 SEC – JumpIchiban such as a blue Animal Kingdom Pirates deck or a purple Straw Hat Crew deck One Piece Card Game -

The copy effect lasts indefinitely

Often too difficult to cast, the upside is rarely worth destroying your mana base for

Magic rules takes a lot of text and requires additional processing complexity

Dishonorable Mentions: Rhystic Study + Smothering Tithe Rhystic Study and Smothering Tithe are two of Commander's strongest cards because you have three opponents to trigger them and time to play 3- and 4-mana enchantments that don't impact the board

You control your opponents while they're searching their libraries

Ezio, Auditore da Firenze + Jensen Carthalion, Druid Exile Waning a bit after last years excitement, Ezio Auditore da Firenze is a fun casual assassin typal commander, but the real reason folks tried to make this work in cEDH was that its a 5-color 2-drop commander with nary an assassin in the deck