This is a pain in my ass: I'm building an H-bridge to power a motor which draws 1.5A without load and 15A at stall when given a supply voltage of 8V. I'm using two NPN and two PNP transistors. I'm using +5V as high signal. I'm going to use PWM on this thing. Can anyone here adivse me on what transistors to use? I'm searching on this for days.
OK. There are some Bipolar
OK. There are some Bipolar Junction Transistor (BJT) (npn or pnp transistors) that will handle that kind of current. Try googling for “npn” or “pnp” along with “15 amps”. However for this kind of power, you might consider some other approaches using Field Effect Transistors (FET) and/or relays.
GroG has a great h-bridge matix post in which he listed some good designs from several LMR members. Unfortunately, the images for the post are missing, and he did not include links to the original designs from their creators. I’ve let him know about this, so hopefully he will get around to updating the post.
In the meantime, you should be able to search for posts related to those designs. Chris the Carpenter did an implementation of the BaseOverApex big motor driver.
I have been googling for
I have been googling for days now, the problem is that there are just to many choices. And that I need a transistor which will switch at 5V. I cannot seem to find how to work with FETs so I have not a clue how to build an H-bridge with them.
And indeed, almost all schematics are missing 
anyway, thanks… My search continues
Wrong
EDIT: wrong
Wait!
I think I found them… Not an expert on this, so could you please check these two:
Thanks in advance!
I think those should work
I think those should work for you. Actually, since you are not driving them anywhere near the top voltage, the BD909/BD910 NPN/PNP complementary pair should work just as well. So get whichever is available.
Buy heat sinks and heat sink compound to use as well.
The pictures in the h-bridge
The pictures in the h-bridge matrix post have been fixed. (Thanks, GroG!)