I was looking for resources and have found a huge bundle of battlers made by Aekashics.
They have a very distinct graphic design, so you have to decide if they're good for you, but they're original and different:
Aekashics megapack (https://aekashics.itch.io/aekashics-librarium-librarium-static-batch-megapack)
If you like what you see it seems there are animated battlers too, but I think that requires a patreon.
The link I'm sharing are free battlers. Almost 900 of them
Hope you find it useful