Shadow clones - make duplicates of myself and send them to school or work to do boring stuff for me while I go have fun doing random shit. Also I could increase my productivity, income, have multiple jobs, win fights, so many various useful things...
Kamui - most effective against bullets probably. I'd rob banks and stuff. And I have my own quiet dimension just to myself if I just needed a space. I'd throw parties in the kamui dimension, lol.
FTG - leave a marking every time I go visit somewhere so I can teleport back there at a moment's notice. Literally no need for transportation.
Medical ninjutsu - to save other people's lives.
Mu's invisibility - Being invisible would be awesome, you could get away with so much stuff.
Mu/Onoki's flying technique - flying is awesome, no explanation needed.
Tsukuyomi - mindf*ck people if I wanted to. Genjutsu in general would be cool because you can sort of control other people without them realizing it, but Tsukuyomi is especially cool because it has that time hax of 72 hours in 3 seconds. I could also use it on myself if I looked in a mirror, lol..
Mind Transfer - control other people. Hehehehehe
Edo Tensei - bring back loved ones. Or historical figures / people from hundreds of years ago to learn about the past and stuff.
Muki Tensei - control all inorganic compounds. Very versatile with many uses
Deep Forest emergence - build houses, grow forests, endless supply of lumber lol.