I like the slate, but think as it is, it is missing representation for some ideas which could end up being really fun. I'll group them according to the category into which I think they fit:
"X-type of move is made viable via the rest of the kit, and/or the rest of the kit needs this to be viable"
Concepts: When All You Have is a Hammer, Perfect Conditions, Another STAB at It, Big Numbers
Hammer already does this very well (how moves help moves). But this sort of chicken-and-egg problem, in which is it the kit that makes the specified thing work, or the specified thing makes the kit work, is interesting enough that we can also explore things that are improved by/improve things of a different category (conditions by kit, pseudo-STAB by typing, or "bad" move/typing by stats). I think something more abstract (conditions) would make for an interesting difference with Hammer, but something more concrete (extra STAB, dummy thick stats) could pose subtler questions.
"Support self (but in a bit freaky way, while affecting your team-building)"
Concepts: Selfish Support, Only Room for One, Atypical Abuser
The mismatch with typical team expectations poses very interesting questions which aren't explored by other things on the slate. For Selfish Support or Room, how do you keep your supportive move from helping your teammates? Is this sort of self-sustained mode even possible? I think Medic on the slate is still more agnostic towards its teammates in that way, or more focused on its own contradiction, but excluding teammates from your strategy and the ramifications of it (you can be run on any team) is very interesting to me. Atypical Abuser is sort of the opposite in that its type profile/moves would improve diversity of specific kinds of teams, but still great.
"Anti-Meta"
Concepts: Jewel Breaker, Defensive Nullification
Studying the most popular tools by breaking them, what's not to like? An anti-Tera mon, like Zacian was anti-Dynamax in VGC, could be great (and was in fact my own initial idea) and I believe that was why the Stellar was introduced, although the ban of the best mon at abusing it did not allow us to explore this. Defensive Nullification is more targeted, and I would be excited to see how the one Pokemon would affect these tools once it is introduced into the meta.
Also, Ambidextrous Abilities is different enough from Which Road... (in that it asks for different roles) that I think it could also be considered.