These are incredibly lovely! The pastel combinations make them very playful but bright and cheery. Perhaps they should change the "signatures" here to just be designated sticker books! Anyway, you're very talented and creative.
Might I suggest a few more common titles (some of which you did note as a coming soon option) for artistic consideration:
You could do a "royal family" set since you have princess by including prince, king, and queen options.
You could also do an "attitude" set that include words like silly, playful, twisty, bubbly, sweet, and cute.
You could do an "action" set like spank, time out, lines, chores, rules, regress, forced, bedtime, and grounded.
You could do an "relationship status" set like mine, his, hers, theirs, taken, owned, collared, and loved.
There is also the furry group of regressors to not forget:
Anyway, those were my thoughts. I'm looking forward to seeing the rest of the beautiful stickers that are created and posted.