Most electronic appliances, i.e. TV, radio, computer etc. just convert the mains to a DC voltage so the frequency is unimportant.
Heaters and incandescent lights are purely resistive so it doesn't matter whether it's AC or DC, let alone the frequency.
Most motorised appliances, hand drill, vacuum cleaner, food mixer etc. use universal motors which will are unaffected by frequency.
There are some motorised appliances which use induction motors which are effected by a change in frequency and some transformers designed for operation at 60Hz will run hot at 50Hz so need to be derated and like you say, some appliances use the mains frequency as a timebase.