A little-known page on Steam ranks unreleased games according to the number of Wishlists they’ve garnered so far, though the exact metrics being tracked are still somewhat unclear.
The "Top Wishlists" page itself currently lists 196 unreleased games according to the amount of Wishlist attention they’ve received. Right now, Sekiro: Shadows Die Twice, the Resident Evil 2 remake, and Metro Exodus lead the category, though developers that have compared the rankings against their own metrics suspect that the list ranks recent wishlists for unreleased games rather than total wishlists received to-date.
And while neither that time period nor the number of wishlists themselves are displayed in the ranking, the data can still potentially provide other developers with useful insight into what unreleased titles are attracting attention on Valve’s digital marketplace and how their own titles stack up against other heavy hitters.
Many devs have used both their own data and information from others to try and suss out the importance of wishlists to a game's post-release performance on Steam. Some, like Grey Alien Games' Jake Birkett, have previously used that data to work out roughly how often wishlists convert into actual sales and the relationship between a game's wishlist popularity and early sales numbers.