There aren't true 1:1 clones, but there's ripgrep (inspired by GNU grep) and fd (inspired by GNU find). Those two I like, though. I think they're thoughtfully designed and in ripgrep's case at least (I just haven't read posts/comments by fd's author), it was developed with some close study of other grep implementations. I still use GNU grep and GNU find as well, but rg and fd are often nice for me.