I just take a small tool box with the basics (wrenches, zip ties, wire, etc), air tank, jack with jack stands, sun screen, food & drinks.
The tool I use the most at the track is my tire pressure gauge.
If I break something small, I fix it. If I break something bigger I just go home and fix it, rather than thrash in the pits....been there, done that too many times. Good luck, and have fun.