For mobile or specific archived builds, sites like APKMirror or Uptodown host version histories, though these are typically for Android .apk files rather than PC .rar or .zip archives.
You can often find legacy builds and the latest stable release on the official Mindustry Itch.io page . Mindustry.Build.140.3.rar
The most reliable source for previous desktop versions (in .jar or source format) is the Anuken/Mindustry Releases page. For mobile or specific archived builds, sites like