Oddballz Neo is full of Eggz, textures, PopBox songs, and all manner of other fascinating downloads. It also has a comprehensive list of breeds, as well as several well-made information sections. If you are seeking to improve your Oddballz experience, this is the place to go.
For those who'd rather design their own Eggz,The Odd Planet is home to Eggz Scrambler, an excellent tool whose development has sadly been halted. However, you can still get it, along with the Petz Installer and Packager programs, which makes packing and unpacking all your Eggz (and other Petz games' files) a snap.