Steam Spy
A long-running market-data site that samples public Steam profiles to estimate ownership, playtime, tags, and audience distribution.
Why use it
Use Steam Spy for inexpensive historical genre scans, rough competitor filtering, and publisher-portfolio research.
Where it fits
Study the market and the players you want to reach, then turn a loose idea into something you can test.
What to check
Sampling is noisy for small or newly released games and some data is Patreon-gated; ownership must not be treated as exact sales.