Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
These are the winrates computed for randomized formats. They're hosted on GitHub Gists, which is much easier for me to add large quantities of text to compared to Smogon.
March 2021 winrates for [Gen 8] Random Doubles Battle and [Gen 8] Random Battles (No Dmax) are available! Regular [Gen 8] Random Battle statistics are also available now!