Not to mention pullups of every possible variety under the sun.
Wide grip
Narrow grip
Parallel grip
fingertip
over/under (one hand over, one under... just like it sounds)
Chins (double underhand)
Under/Parallel
One hand higher than the other
Using a tennis ball to grip
Using ropes
Using woodwn dowels
one handed
weighted
using rings
band assist...
You get the picture.