cademan I do too, not sure where to get market watch data or if Steam publicly releases "wishlist" data as that helps publishers decided when to discount a game. There are top selling game lists on the App store, and it's easy to genre specify and make sub lists.
There is a old movie rule of thumb-- if a certain movie is released too much, then you stop releasing those kinds of movies, but if a trend is about to happen you make that kind of movie.
Meaning, if there are a lot of new puzzle games like "Bejeweled" or "Candy-crush" then making another one probably won't be a good idea. However, after a certain period of time making the next "Candy-crush", people will enjoy it as it has nostalgia value and brings something new to the gameplay.
Notably, this is a rule of thumb and doesn't account for new things like "Minecraft" and the failure to bring back Westerns as a film gerne. However, there was a game simulator I played that consider creating different game types based on market watches and trends in order to have a better chance at selling a game.