eeprom 27C512 or 27512 (64KB /512Kb) ,they're used but they've been cleaned and erased.
If you need or prefer a particular brand or ref,please let me know,I have much different brands and refs.
And for the case you wouldn't have an eeprom programmer,I'll also flash the eeproms for you,test them and place a label. Just send me binaries by mail or give me the link to download them if they're available on the web.
These EEproms are perfect for colecovision homebrew players and Vectrex Homebrew players