Night Cafe. Free to use but limited uses. Can log in daily for 5 coins, do other tasks for some more. I found it pretty easy to save up a few days then go on sprees of trying things. There is a totally free option there too but it doesn’t have some of the finesse of the coin use ones.

There are also daily challenges and community challenges, which I think are great to help with ideas. And some of the communities if come across are very helpful with things to add, or add as negative prompts, etc. There is a “group” of artists who leave their prompts open to see too. So when you look through or vote on the other art, you can click to see info and those folks have the prompts they used visible for that piece, in case it’s helpful to you.

https://tinybots.net/artbot and by extension https://aihorde.net hundreds of sd models, all Loras in civitai, completely free and without ads and free software.

edit: just looked at that tinybots.net and looks amazing. pretend i didnt suggest anything lol

If you have a big GPU stable diffusion webui/easy diffusion will run on your own PC. There is also an option to use CPU if you have time