I did a quick survey of the commonly available 6x15mm motors for Tiny Whoops. The KV rating (rpms for every volt applied) is probably the best for comparison purposes since rpms vary across the voltage range of the battery. That said, some motors only specify rpms. In that case, we assume the voltage is for the nominal 3.7V and derive the KV rating.
|KV||RPM @ 3.7V|
*No specified KV rating; Value derived from claimed rpm.