Well, if you only plan to do one more, this could actually be the penultimate list. But if this is the last one, then the previous one would have been penultimate.
Mind you, I’m 100% okay with using penultimate to mean second best, instead of the actual definition as next to last. It makes sense as a non standard/slang usage, since the last is often the best (depending on the list, of course, but most save the best for last). It’s a good play on the way we use ultimate as both final/last as well as best.
One of these days, the dictionaries will catch up to this usage and it’ll become a standard usage, so you’re getting in on the penultimate use of penultimate as slang, in a way :)