https://f95zone.to/threads/koikatu-repack-rx20-illusion.14554/ is probably the best customizer/sex simulator available. Tons of options available and literally hundreds or maybe even thousands of fan-made models to download from every walk of media. If theres a character you want from an anime, cartoon, game, or sometimes even real people, chances are you can download a model for it. Not much for gameplay though, pretty much just walk around and have sex with them.
https://f95zone.to/threads/artificial-academy-2-mini-12-7-illusion.1336/ from what I understand is similar. Little more gameplay, less customization available.