As a campag guy, we have needed a long t-handle t25 to install ergo levers since the 11-speed days. t25 is by far, as far as this relative luddite is concerned the most popular torx size used on a bicycle.
My garage has 1/4 and 3/8" socket based bit kits for car, motorcycle and general tinkering stuff, but for my bike related uses, the feedback t-handles have been more than good enough for me.
