Chordbot is my go to Song sketching app Waaaay worth the pro price but the free version is great.
TouchDAw: A great control program with a keyboard and xy pads that wirelessly connects your tablet or phone to your daw of choice via wifi or bluetooth.
LoopStack: Just what it sounds like a looper that WORKS. A great way to get ideas out quickly that also comes with some effects
FL studio Mobile: Already a favorite among alot of producers and musicians now available for your mobile device
IRig: If you haven't picked one of these up you are missing out especially in the age of youtube where there is nothing worse than a musician putting up a video with crappy sound. Our greatest business card is our music don't put yourself at a disadvantage by using your phones mic. I have the IRig Pre and Mic Cast and haven't looked back.
Timesheet: Is my go to billing tracker while juggling multiple clients and projects
Hope I didn't throw too much at you guys. Happy Recording