Since this group is on its deathbed, here are some better, more active original character groups to check out! If you enjoy the submissions in this group, these groups should also interest you:
Thought-Up is all about original characters (no fan characters or fan art), and they run lots of fun activities where you get to draw your own characters in situations you might not have thought of! This group is still a bit on the small side, but I know that with some more members it'll be awesome, and the sort of group I wish OCA could have been.
In addition, here are a couple of more specific groups that I think are worth checking out:
Traditional-OCs is for humanoid OCs drawn using traditional media. Aside from those two specifications, their rules are very similar to ours, so OCA members should feel right at home.
CharacterRealism, like its name suggests, is for OCs drawn in a realistic style. It looks like their interpretation of "realistic" is fairly broad, so check it out even if you're not into super-realistic art!