This depends very much on the kit I'm working on.
1.5 mm driver
2mm driver is a must have. 2mm ball ended as well.
2.5mm driver for motor mount screws. May need a ball ended one depending on kit.
Tamiya combo shock shaft pliers/ballend tool thingy.
Long nose/needle nose pliers.
JIS PH2 screwdriver.
Small flat head screwdriver, approx 2mm width.
Side cutters/nippers.