Even years after its release, 1.12.2 continues to be a primary hub for modders for several reasons:

Tools like Prism Launcher or GDLauncher allow you to create "Instances." You can set the "Instance Path" to a portable drive.

If you are looking for a way to keep your mods "portable" (meaning you can run them from a USB drive or a specific folder without messing up your main game files), here are the best practices:

In the standard launcher, you can go to "Installations," edit your 1.12.2 profile, and change the Game Directory . This ensures your mods, saves, and configs stay in one specific folder rather than %appdata% .