I am specifically asking about my HT-1, but I can't really find any good lists of anything out there for other bikes either.

From the original tool kit, mine still has the 13/17mm open end wrench, 13mm "socket"/screw driver handle, the flat head/small cross point, the large cross point, and the small pliers. 

I have added 6, 8, and 10mm combo wrenches.

I would like to have a spark plug socket, but need to find one that I can either turn with a 17mm wrench or a small 3/8" breaker bar. If I add a breaker bar, I would also toss in 10, 13, 17, and 19mm sockets and I think that would be the max I could fit in there.

Also, are there any readily available little cloth tool pouches to replace the original vinyl one? Mine is shreaded and sticky.