There's no official tracking site for Deadlock's heroes or players yet, mostly because the meta is so fluid right now. Everything's in a constant state of change, and Valve probably has bigger fish to fry as it works to get the MOBA to its finished product.
The most popular unofficial tracker that players have been using is Tracklock. This has tons of information on various heroes and even some of the top players. Recently, the site revealed the most-played heroes as well as the ones with the highest win rates.
While it's definitely interesting to see which heroes players are naturally flocking towards, and what your predicted MMR is, the site isn't 100% accurate as it is unofficial. Everything on it should be taken with a grain of salt. But now, after further intervention from Valve, it looks like Tracklock will have an even harder time accurately predicting stats.
"Valve turned on even more aggressive rate limits, and now there are no new games being tracked," one of Tracklock's creators said in a now-deleted post in the community Discord. "We will be making some changes to the site soon to accommodate for this. I would just like to say, do not go and complain to Valve. This game is in beta, and they clearly aren't ready for stats sites yet. We will take this time to improve features (we are only a week old!) and be ready when Valve has a solution for us!"
Tracklock was good for showing which heroes were the most/least popular, but it did fall short in accurately placing players' MMR. It often wouldn't account for how long someone had been playing, so there were people placing in the top percentage with only minimal playtime.
"Honestly, a good change for a game in a PLAYTEST," one player says. "I disliked the tracking of MMR since the trackers popped up; it created a competitive scene in a game when the developers do not really want one yet."
Others point out that inaccurate MMR ranking doesn't really help anyone. For those who actually want to know their ranking, it's best to wait until Valve has an official response or a more accurate method. Plus, with Deadlock still in its early stages, not only has the MMR proved to be a bit finicky, but there's also no telling how quickly the meta will change day to day, rendering one hero redundant while another becomes overpowered.