Single arm hammer preacher, single arm db preacher, preacher concentration curls, pinwheel curls (either dumbbell or rope attachment, I double it up in my hand for extra forearm work), spider curls. With Db movements I like to have to wrist facing up but slightly pointing in the direction pulling away from it. I'm soon to receive an award for most terrible description of exercise execution, ever. OK, imagine yourself seated on a preacher bench, dumbbell in hand. As you curl upwards, instead of pulling straight towards your face, I turn my wrist slightly so that the top of the movement for my right arm would put the dumbbell more so beside my right ear.
I'm sorry I smoke way too much fuckin weed in the morning
I'm not a big fan of single arm/legged exercises even though i am fully aware of their value. I just don't love doing them. However, for biceps my fav has to be the Single Arm Dumbbell Preacher Curl for the simple reason that the movement removes any and all other possible misfires, cheats, help, whatever you want to call it, etc. In some ways, it's almost like the purest and perfect (if such a thing even existed) biceps movement.