Seems no one has mentioned the Haskell error index yet. Probably because type errors do not feature there much. However, the index aims to provide examples like this one.
Perhaps the contents of your blog post eventually can help to update the error index examples.
A particularly hard-to-spot error (at least for me) were the effects of simplified subsumption, which was introduced in GHC 9 and can lead to very strange and cryptic error messages when higher-rank types (e.g. lenses) are involved.