So I probably oughtn't have opinions on this as honestly I spent a lot of time on each character, but I do have a few favorites.

• All the Mimics. They were a pain to make so I spent a lot of time on each of them.
• All the Archmages as well. They're meant to be egotistical yet reliant on others to do a lot of helping out, which is a fun thing to play with.
• Proinsias, Lich Assassin and Ardal, Lich Survivalist, because those seem like amusing paths for Liches to have gone down.
• Nomusa, Minos Acrobat because it's a true "bull in a china shop" situation. Their racial passive makes them not actually benefit much from their class bonus to Evasion, but their reduced damage from AoE attacks and their chance to counter single-target attacks makes them work great in that odd tank role regardless.
• Presert, Gruub Berserker has massive critical chance so if they can stay alive their small stature really works well with a Greataxe.
• Hamlet, Gnome Cheerleader, because in the original Hamlet there is no more wrong thing to call him than cheerful.
• Ufuoma, Void Child Inquisitor. The Inquisitors were originally going to be a DEV/ARM class, but were changed to DEV/AGI. So Condemn instead of dealing damage based on DEV and debuffing the user's DEV, did both to ARM. Ufuoma is the only one that has Condemn replaced with Foreordain, which remains an ARM-based skill.
• Tjarrd, Slime Hero is just fun to play as. No equipment but high base stats and extra actions, with Mp Regen to mitigate the Hero's high cost skills. As close to a Dragon Quest OC as I'll ever make, I think lol.

There's more but those are the ones that come to mind immediately, and I've already gone past what's probably the limit on favorites, ha ha.