6. Google ImageFx

Google released ImageFx in February this year alongside its MusicFX and TextFX models as a way to gin up hype for its AI initiatives invading Android and its load of other apps. It’s all available in Labs, which is Google’s experimental branch of services. You have to sign up to gain access, and space depends on Google’s whims.
Still, if you manage to get access, ImageFx is one of the better free services available simply because there’s no credit system, and you can create as many images as you might like. It also offers synonyms for certain nouns or verbs, though maybe not in many ways that are very helpful. Unfortunately, the system is also very restrictive in what you might use as your prompt. Some of the generated images are quite appealing, while others are very, very bland.