Let's see, what hasn't been picked out here yet? Ah, yeah..
Joy Mech Fight
Akumajou Densetsu
Splatterhouse: Wanpaku Graffiti
Boku Dracula-kun
And for the sheer novelty of it, any Hong Kong Original Famicom pirate you find, even if it sucks.
If you're able to find an area where you can get loads of FDS Disks on the cheap as well, it might be a good idea to get a Famicom Disk System.
Of any games I'd be willing to sell, the only ones I got are some spare FDS commons, such as Ice Hockey or Tennis.