Thanks for the help everyone!! I think I’m going to start of with Cayenne, Seranno, and I was thinking of Pepperoncini!
You can't go wrong with those mid-hot peppers. Not so hot that you can't enjoy the flavor.
If you want to try a superhot, Carolina Reapers (current record-holder for heat) and Bhut Jolokia (ghost peppers) are fun and easy to grow. I grow them to give to a local brewery to use in their pepper porter every year. Otherwise, I don't often use them myself. The things are terrifying. However, you can take one pepper, cut it in half and scrape out and toss out the seeds, then add the pepper (or even just one half) to a big pot of chili. You'll have a nice, balanced chili with just enough heat to get your attention. I put the pepper on a wooden BBQ skewer, stick it in the chili and let it infuse a few hours. The skewer is so you can remove the pepper before serving--you don't want that left in there. And don't get any seeds in the chili--you'll know why if you bite down on one.