Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

Yes. Various, with various limitations.

The simplest is Stable Horde/AI horde. Volunteers donate GPU time to the public. Please do not abuse this trust by overusing it without giving back! Great for quick experiments, though, since it requires no sign-up. Also includes a "get probable description from uploaded image" function, I’ve just noticed:

https://aqualxx.github.io/stable-ui/about

Personally, I’ve been playing around with leonardo.ai. It has a payment structure, but the free tier is very generous, in my opinion. You get 150 free daily token. Images cost between 1-4 token. It has a prompt generator, and you can even train your own model for free. There are also a lot of community models, since every model is set to public by default. You can even browse public images and directly copy all settings/prompts into the generator or use them for image-to-image stuff.

The company is very much focussing on building an active community, which can be both good and bad. You are first put on a waiting list, but your account is automatically activated if you join the discord and write some comments. There are also constant community contests/challenges to earn more token.

https://leonardo.ai/

Edit: leonardo.ai techncally allows nsfw generations, but heavily discourages them. It has an automatic filter for any terms deemed nsfw. You may also not discuss how to circumvent that filter in the discord. (You may discuss how to bypass the filter to prompt safe for work images. E.g. you may discuss how to create Charles Dickens characters despite Dickens being filtered out.)

Here are few more, but I haven’t tried any of them:
https://stable-diffusion-art.com/free-ai-image-generator-sites/