If you study undergraduate medicine, mnemonics are almost indispensable - there is so much factual material to learn. I was never given any mnemonics in my time as a maths undegraduate. But Robert Israel just mentioned "iciacids" to help remember the important features when looking at a function plot Function - Main Features? I would certainly have forgotten some of them.
So maybe mnemonics are useful for maths too. Maybe also for tricky proofs? Or for areas knee-deep in definitions, like topology? Does anyone know of a source for math mnemonics? Eg a top 10 type website? Or a kind of successor to sci.math FAQs (although I do not remember any mnemonics there)? Or a book?