Mnemonics

"flipflop", "float", "form", "function"

Mostly harmless, but there is a smattering of extra uses.

Operators containing this character

ff and fff create flipflop ranges

When used inside regexes

\f is a form feed character, the same as in interpolated strings

As an adverb

:f applied to a generalized quote interpolates and calls

Other Uses

%f in a printf format outputs a number in floating point format
\f in interpolated strings represents a form feed