I'm not sure what you mean by, "power they can handle". Every electric motor has maximum/design ratings for volts, amps, rpm, and power output (torque at the motor shaft). Find some motors from online sellers and look at the information. You'll get an idea of what is available.
Generally speaking, the larger the motor, the more power (volts and/or amps) it consumes and the more torque it can provide. There are exceptions, of course. Shaft speed (rpm) can be just about anything from a few hundred rpm to well over 10000 rpm. However, the shaft speed may be rated as "free", meaning that speed is measured with no load on the shaft. Attaching something to the shaft may dramatically lower the operating rpm.
There are also "gear motors" with built-in reduction gears*. They trade shaft speed for torque. A perfect example is a power window motor in your car door. The window doesn't need to move up and down very quickly, but it can be heavy, and there is limited space inside the door for a large motor.
* Gear-motors can also be built to increase shaft speed, but that is rare.