I collected for almost 20 years before kids/life took over
. I sold off a good chunk, but do have quite a few still.
Rare: Some prototypes for the PS2 (naruto and one of the .hacks), cyberbike cib, gc pokemon big box sealed, f1 2009 sealed, MT Punch Out sealed, a few game sets/bundles for the PS2 that don't pop up often like the ESA bundle and the goosebumps w/ book.
Valuable: I haven't looked up prices in quite awhile, but still have some that I'm sure are still up there. Little samson, Powerblade 2, Gun Nac, sculptor's cut, Megaman X2/X3/7, Cubivore, MUSHA, Tron Bonne. I still have my PS2 set, so whatever good ones are in there like Rule of Rose and Kuon.