I honestly don’t know why people who want herbivorous pets choose to get dogs or cats. Rabbits and guinea pigs are lovely creatures. Rodents, birds, and certain lizards all make very good vegetarian companions, so why not choose one of those?
I have a personal love for tiny screaming dinosaurs, but having also kept rabbits and guinea pigs I’d honestly recommend them.
I made a couple of mods and published them on Nexus, and with the donation programme actually made a little money from it, even though I didn’t expect anything. If you want to make money modding without completely shitting up the user experience you’re better off just shoving them on Nexus and maybe making a ko-fi or something.