exe7(Q)+
Longest individual notation?
I would probably say Qg2xd5# since it is a doubly disambiguated queen capture checkmate and it includes the biggest letters and numbers in the alphabet.
Q, g, d, 5, and 2
example:
If we're counting less commonly used methods of notation which are still technically following the rules of notation, I propose:
pexd6 e.p. dc #
maybe if you manipulate the board so this could happen, it could be like
2372. exd8e.p.=Q#1-0 (20 including spaces and periods, 18 without periods, 17 without space or periods.)
including some methods like move number, en passant, 1-0 (win) and pawn promotion?
You can't have an en passant on the 8th rank. Also, you could increase that number from 2372 to 237200.
So true