Not really. Most years I create the list in August-September time, giving me enough to time to do my research and write the little bios for the trophies. I often take suggestions on board, and will sometimes head off and do research on characters from games I'm not so familiar with. Many of the Fire Emblem characters I've done have been suggestions, for example. But I certainly don't guarantee I'll draw any suggestions. Black Shadow from F-Zero has been on my list for about 5 years. He just gets bumped for scarier monsters.
I did request slots in 2014 - but you had to donate a certain amount to charity to get a slot. Being unable to plan made the challenge of drawing one every day WAY more complicated. So I'm not sure I'll do it again. However, I may open commissions in the near future. This won't necessarily be a Nintober thing, but I need some extra cash for the Nintendo Switch!