Steam sales may be a long running tradition, but the awards aspect is relatively new, having only started up in 2016. Back then, they were a little tongue in cheek, featuring categories like "Villain Most In Need Of A Hug," and "Best Use Of A Farm Animal." This year seems a bit more straightforward, with categories for Game of the Year, Best Developer and Better with Friends.
There's also some fuzzy math involved --
may have officially hit version 1.0 this year, but thanks to Steam Early Access, it's been available since 2017.
Either way, here's the full list of contenders and categories: