Originally Posted by JSemple3:
“Has a max ever been done in any of the major finals? Masters/UK/World?”
Worlds, definitely not. Stephen Hendry v Jimmy White (1995 semi final) is the only maximum in a one table setup at the Crucible.
UK, obviously Neil Robertson today which makes him the first ever!

Previous to that Ronnie O'Sullivan (2007) and Mark Selby (2013) had made maxes in the semifinals.
Only 3 maxes ever at Masters too: Kirk Stevens (1984, semi-final), Ding Junhui (2007, wildcard round) and Marco Fu (2015, first round)
In ranking events, I seem to recall Ronnie O'Sullivan maxing a maximum in the final frame to win the Welsh Open last year too