Are they valuable? If you sell them individually and only get $1 or $2 each for them, it's probably not worth the time and effort by the time eBay and Paypal take their cut and you need to package them and take them to the post office. On the other hand, if you sell them all in a single lot you might not attract as many potential buyers (because some people might only want a few of them, so they won't bid on a lot of 23).
Good luck!
I dunno if they'd be valuable or not. Seems like most "valuable" movie memorabilia is either high class stuff (like actual props or signatures) or it's older (like, I'm sure if say found say, an original Star Wars lobby poster.) But there are just plastic posters, so.. dunno. I'm sure some of them would be more popular than others (like bet I wouldn't any problem off-loading the John Wick 2 poster, for example, but The Boss might be a different story...)