I don’t know of any good roundups of different pipe operators that people have invented! Sounds like something somebody ought to write
If you just want to find out what’s out there, you can try doing an R Site Search for “pipe operator”, which will find all the functions on CRAN with that term in their description (note that most of the results are people re-exporting the magrittr pipe in their packages).
P.S. I suspect this question might draw more attention with a slightly clearer title — when I clicked on it, I thought it might be about building analysis pipelines (multi-step processes chaining together different tools), not pipe operators. You could try editing to something along the lines of “Which packages have useful pipe operators?”.