The free image generations are not that great with their results and they could still face restrictions and waiting times to use these images.

The DeepAI AI Image Generator is free, and it is giving good results.

A few days ago I used it to generate dozens of images in a few minutes, and I have not seen any restrictions so far.

DeepAI nowadays provide probably one of the best AI image generators.

If not the best.

And the generated images are public domain.

You can use them both for personal and for commercial purposes too, including for NFTs too.