Deceiver Exarch

In Commander, Deceiver Exarch earns its slot almost exclusively as a combo piece — the instant-speed entry matters because you can drop it on an opponent's end step and untap Kiki-Jiki, Mirror Breaker before anyone can cleanly interact. In Modern it was a defining combo threat before Splinter Twin was banned, and it remains legal but largely orphaned now that the enchantment is gone from the format. Legacy and Vintage have access to faster, more resilient combo infrastructure, so Deceiver Exarch rarely competes there. It's not legal in Pioneer, Standard, or Pauper, which narrows the practical conversation to Commander and the occasional Modern fringe build.