301's. Rocketeers, 201's, 19-51's or 19-50's, 401's...
Almost any vintage Bernina, Elna...oops you only asked about Singers..
I've always picked up any accessories at a reasonable price, buttonholers, zig-zagers, rufflers (I must have 15 of 'em and I'd love to get rid of a few at this point, they're in almost every box!)