Economy pouch toolset in the under-seat compartment. Includes (w/ my additions) two wrenches, 8 allen keys, 5 zip ties, 2 safety pins, locktite tube, plug socket (w/ an extra plug inside), pen flashlight, multi-bit screw driver, tire pressure gauge. Takes some massage to fit it all in there but it works. I always carry a Kryptonite EV lock. It's usually on the frame side just above the front cylinder.
Still looking for good spots to fit a spare lever, mini adjustable wrench or a vice grip, a Leatherman and possibly a tail bulb. That said, I've never needed any of them on the road, so as long as they fit somewhere without ruining the bike's contours I don't mind. In beemer state of mind on longer/overnight rides I'm open to using a tank bag with other stuff like a flat tire repair kit.