I don’t think there are anymore U yoyos. I checked the lists of brands on yoyoexpert, and unless I misssed one, there weren’t anymore. So I made one up.
Useless yoyo from the dollar store.
Ultimate Soldiers - qixia
they make another that starts with a U, but I’ll save that for next round.
Velocity
was used already
^
valve
i didn’t it was already used and it was my own thread, lol.
Whale- Adegle
Xodus-Yomega
this one was hard. 
Y is for YWET
Zen by Shinwoo
Ai-YYJ
Bassalope
C-note, aw yeah!!!
Destiny by god tricks
Equinox
Frantic
G funk
Hectic
I-I-I-just don’t know! 
Immortal Star (Aoda)
Jamboo
Kickside