This software is called minecraft_instance_manager. It is written in python and has command-line interface, but it is still quite easy to use. This program makes possible to have multiple instances of Minecraft with their own set of mods, resourcepacks, etc., which is useful if you have a big set of mods for different modded worlds or servers. It is quite annoying to copy needed and unneeded mods again and again, right? Yes, I know, sound like another MultiMC. However, in my opinion, it has an advantage over MultiMC. You don’t have to use a specific launcher for this purpose. You just open this program, where you can create, rename, delete and select Minecraft instances. Then you select the active instance and Minecraft folder (.minecraft) becomes a symlink, that is targeted at the selected instance, so make sure that you have made a backup of your worlds. After that you can just continue using the original launcher or whatever you had been using before.
I am not actually sure, if similar software exists, so I just hope that you may find it useful.