Where can i sell and also get stuff appraised at ? for example old basketball cards, old painting etc...?

Hi guys i live in washington,dc and my uncle has antique tv's that still work, old basketball cards in perfect condition in cases and also these old paintings based on lord of the rings before any of the movies i think they had the paintings since the late 70's. i would like to know where could i get this stuff appraised and also sell them at ? do any of you guy know anywhere in d.c where i could do this?