If your goal is to save storage space on a small SSD or HDD, you do not need to download sketchy files. You can compress the official Steam installation yourself using built-in Windows tools or specialized open-source software. Method 1: Using Windows CompactOS (CompactGUI)

The concept of a "highly compressed" Team Fortress 2 is a popular topic in modding communities, usually centered on fitting the massive 20GB+ game into a tiny footprint for low-end hardware or archival purposes

Avoid repacks. Use the official free version.

If you have slow internet, use a friend’s Steam backup or download the official version at a library/cafe. If you need an offline portable version for old PCs or LAN parties, search for reputable repackers only (FitGirl, DODI, Masquerade) – but expect 8–12 GB downloads, not 500 MB.