+1 for Hippy Seed Company They are a little more expensive than some other vendors, but their seeds always seem to grow true for me.
I also recommend White Hot Peppers and Texas Hot Peppers as long as you are OK with open-pollinated seeds and don't mind getting the occasional surprise cross.
If you are interested in more colorful and ornamental varieties, then Matt's Peppers seems to focus more on those. I have seen variations in the seeds I have grown from him, so I would assume that his seeds are likely open-pollinated as well.
Welcome back @gnomepunter. Here are a few links I've collected. No guarantees they still work, especially the non-USA ones, since most of them don't ship to the USA anymore.
Agree with Baker Creek (www.rareseeds.com) being a good start. But have had good success with Sandia Seed, Seed Savers Ex, Bohica Pepper Hut and Totally tomatoes for sweet peppers and tomatoes for sure. Trying Refining Fire Chilis and Tyler Farms for the first time this coming season.