Loads of good ones!
McKinney Falls in the SE
Pedernales and Hamilton Pool in the SW
Pace Bend on the Austin side of the Lake
If you want to drive:
Colorado Bend is Awesome(Beautiful and cold chain of Natural pools and a 160,000 year old water fall)
Best place to camp is Hill Country NSA (totally primitive)
There are way to many to list, it all depends on when you want to go.