Yeah a lot of NSS posters, interesting posters from other countries, and autographs from certain people earlier in their career is worth more.
My Dad has a signed photo and letter from Elvis when my Grandpa was in Germany stationed with him framed hanging on the wall. I have never seen an Elvis autograph look that nice, that big, and such a creative look to it before.
As far as posters I just had one go up from being 2,500 a few years back to over 6,000 this year.
Rocky 1Sheet signed by Stallone
Star Wars 3 Sheet signed by FIsher, Hamill, Prowse, Mayhew, Daniels, and Baker
Rocky Horror 1 sheet Boswick, Campbell, Quinn, Curry, and Meatloaf
Santa Sangre Japanese B2 signed by Alejandro Jodorowsky
Flash Gordon Japanese B1 signed by Jones and Anderson
Dracula 1972 AD Quad previously owned by Tom Chantrell