1
(Apart from the empty program of course)
The shortest I could find was this 410 byte beauty:
->++>+++>+>+>++>>+>+>+++>>+>+>++>+++>+++>+>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>+>+>++>>>+++>>>>>+++>+>>>>>>>>>>>>>>>>>>>>>>+++>>>>>>>++>+++>+++>+>>+++>>>+++>+>+++>+>++>+++>>>+>+>+>+>++>+++>+>+>>+++>>>>>>>+>+>>>+>+>++>+++>+++>+>>+++>+++>+>+++>+>++>+++>++>>+>+>++>+++>+>+>>+++>>>+++>+>>>++>+++>+++>+>>+++>>>+++>+>+++>+>>+++>>+++>>+[[>>+[>]+>+[<]<-]>>[>]<+<+++[<]<<+]>>+[>]+++[++++++++++>++[-<++++++++++++++++>]<.<-<]
2
For reference, the shortest brainfuck quine in the linked question is 392 bytes, though you can get a bit shorter if you don't mind negative cells
– Jo King – 2020-01-20T23:34:32.237Feel free to contribute to this site in Brainfuck. – None – 2020-01-20T23:42:30.737