Double sided ratcheting wrench. From Sears. 1/4 and 5/16 for those hard to get after cabinate screws. I think I paid $6 and use it almost every day.
I will buy the next stubby 1/4 and 5/16 nutdrivers I see for the same reason.
6" Pipewrench for getting rounded valve ends to turn when some dumba@@ used his crescent wrench to open those valves on a refer unit.