Cards legal in uEDH but not Commander
All cards with the Conspiracy card type
Balance
Biorhythm
Braids, Cabal Minion
Channel
Coalition Victory
Dockside Extortionist
Emrakul, the Aeons Torn
Erayo, Soratami Ascendant
Fastbond
Flash
Gifts Ungiven
Golos, Tireless Pilgrim
Griselbrand
Hullbreacher
Iona, Shield of Emeria
Jeweled Lotus
Karakas
Leovold, Emissary of Trest
Library of Alexandria
Limited Resources
Lutri, the Spellchaser
Mana Crypt
Nadu, Winged Wisdom
Panoptic Mirror
Paradox Engine
Primeval Titan
Prophet of Kruphix
Recurring Nightmare
Rofellos, Llanowar Emissary
Sundering Titan
Sway of the Stars
Sylvan Primordial
Time Vault
Tinker
Tolarian Academy
Trade Secrets
Upheaval
Yawgmoth’s Bargain

Cards legal in Commander but not uEDH
Timetwister