Here's a few polish sales I saw that are still in effect now that Black Friday is over. I'm sure there are more - I may add on to this if I find more!
KB Shimmer - 25% off through Monday with code BLACKFRIDAY25
KL Polish - last chance (I believe I saw that they're finally shutting down for real next week) - everything is $2.99. There's still some good polishes left, too, I'm having to resist the urge to go get some backups! Meanwhile, Kathleen's new brand Lights Lacquer has 20% off everything, too. There's only, like 7 polish colors there so far the last I looked, but there are a couple I've been eyeing there too.
NeVerMind Polish - 30% off storewide, no code needed, thru Dec.2 (and a free top coat and free shipping with $50 orders)
has 25% off "select colors" through Dec.6 - I usually think that can
mean anything, so I checked, and it's a pretty wide selection of colors.
(Their brand-new Winter 2020 collection is naturally not included!)
Live Love Polish has their Just Call Me Holo trio marked down to $28 from the regular price of $48. They also have others marked down.
ILNP has 25% off everything (and double reward points) with code BLACK. It says "Black Friday Weekend" so I assume that's at least through Sunday, if not Monday too.
...and a non-polish one, just because it's apparently someplace that rarely has sales - Glossier has 20% off everything. (Ends Monday, it says.) I've never tried any of their products but I've been eyeing them for ages - everybody seems to love them!