It does a lot fastboot does like flashing a radio image--pushing apks etc without needing SDK/ADB
You can run a2sd commands also
If you run it and type help--think it gives commands available--never tried it
flashing commands are not identical to fastboot, so be careful
not sure of one place to go--I just did a lot of googling when I got good command lines that I used a lot, I copied them to a notepad to paste again when needed. IE radios and apks