I think usually the way to go is the other way around; you find something interesting you want to do and look up how to do that. In the process you will most likely find answers that include tools that come with kali.

If you need some ideas maybe TryHackMe (more beginner friendly) or HackTheBox (kinda expects you to know what you are looking for) are good places to start. There's also tons of write-ups and videos about both of those should you get stuck at any place for too long.

Have fun!