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13 Best Open Source ChatGPT Alternatives
(itsfoss.com)
This is a most excellent place for technology news and articles.
Pretty bad article, but here are my two cents on the actual answer, as of right now:
These perform similar to or better than ChatGPT 3.5, in some cases comparable to 4.
For specific niche applications (role playing, nsfw stories, etc), just search on huggingface.co and read the user reviews.