There's this OC-Tober challenge that's basically an Inktober but you draw your OC's for the prompts. I imagine if you have enough OC's, you shouldn't double down on any.

I've been posting my gradual progress on this front on Twitter, having done Day 1 and every third day after. I'll post a lot of them in a row here, and I don't know whether to wait until I'm done or post them as they continue to go...