To the best of my Knowledge.....
Permanent magnet motors are good: F&P washing machines, small scooter motors, treadmills, windscreen wipers, etc.
Induction motors work, 3 phase and single.
Stepper motors are functional as generators. Microwave oven turntable drives etc
Universal motors, Vaccums, blenders, fans, other high speed, light weight type motors are no good.
And of course there are always car and truck alternators which have efficiency as good as any generator when coupled with an external controller.
Important question is what do you want to so with it and how do you want to drive it?
Some are better at AC power than others, some work better with one type of motive force than another, some work well for charging batteries....
I suggest before you try and pick the road to take, choose the destination first. :0)