Sites like Unblocked Games 67 or Unblocked Games 6969 often host lightweight versions of the game.
Quick comparison (at-a-glance)
Minecraft Classic is the grandfather of all "Unblocked Games Minecraft" you see today. While Mojang removed the official version from their site years ago, archival versions and fan replicas have kept the spirit alive. Unblocked Games Minecraft
Since these are hosted on third-party servers, they do not receive official security patches from Mojang, the original developer. Sites like Unblocked Games 67 or Unblocked Games
Why people look for “unblocked” versions Unblocked Games Minecraft