When you think about it, gebrokts has far less of a rationale than some of these, but people stick to their minhagim. Some that I’ve heard of/seen:
A non-observant family that kept the minhag of not mishing but forgot about pesach dishes/kashering.
Radishes (chabad)
Coffee (chabad)
Gefilte fish cooked square on Pesach to make a chiluk
Not eating fish cooked round.
Nothing that can’t be peeled, whether you actually peel it or not. (Baal Shemske eyniklach AFAIK)
Slightly OT question: Does anyone here keep the Chayei Adam’s shita on Potatoes? 😛