The answer is here:
Kettlebell - Why S&S isn't boring
A lot of ideas...
I often add a press and or a windmill at the top of TGUs. If the TGUs are tough as I have increased weight then a set of presses or pushups afterwards. Or just go back to TGUs
After swings and before hangs I do a couple of sets of pullups with a hang to finish each set... The original S&S just includes the hangs but this works fine. If I feel the TGUs have given me enough work laready then I just hang.
That article has many ideas on what you might do. There is also the KB Strongfirst (TGU,Swi, Sq) dvd and pdf at BJJ Fanatics which has ideas in it as well. The thread above has enough information to keep going for a while.
Good luck in your training.
NB- I should mention I train mainly for health and longevity. Improvements are nice but a secondary effect. These goals influence my approach.