In a Topeak Micro Aero Wedge with a stated capacity of 25 cubic inches, I can fit:
Spare 700x23 tube:
Ultraflate Plus with one cartridge in the chamber:
Two unthreaded 12g carts:
Lifu hex key set (with duct tape to replace the bulky blue holder)
Park Glueless patches:
Park CT-5 chaintool:
Telescoping Crank Bros. Speed Lever:
Not bad for something that small.