The data sheets are so hard to read if you don't know all the stuff in them
I'll let you into a secret most of the time you only look at a few of the things.
All transistors I can find seams to work with really high voltages or with very low amps.
Don't confuse the maximum voltages with the working voltage, typically a transistor might have a collector emitter breakdown voltage of 60V but you wouldn't use it at this voltage, it would be fine for using up to 30V or so.
There are only a few things you need to know:-
Transistor type - NPN or PNP
Package type - surface mount or leaded
Collector current - how much they will pass.
Saturation voltage - the voltage across collector / emitter when the transistor is on. This is important for seeing how much current you can really pass through it. Because this will determine how much heat it burns when it is switching a certain current.
Power dissipation - how good the package is at getting rid of heat.
Gain - ratio of collector current to base current. Normally the bigger the current rating the smaller the gain.
You don't want to know about frequency or bandwidth - you also don't want to pay for it.
Hope that helps.