I have 96 Warhammer paints and 23 are open and the rest unopened where can I sell them

They don't buy used products, even unopened.

I might be interested depending on the cost. No shop will take them though.

Or Letgo

They don't buy used products, try Facebook.

They wont take them. Might have better luck on Facebook or Craigslist

Best i can tell you is call them.