I've started calling them "acoustic" bikes, like non-electric guitars. Not technically accurate, but folks almost always get it and smile.

Another name: bio bikes

Analog bikes

How strange that a non-electric bike now needs a special prefix. To me "bike" is the traditional kind and "e-bike" is the motorized kind. Has it really tilted that far? Not where I live, where probably 10-20% of bikes are electric. So far.