As you don't need to access them any more, you can remove the .desktop files.
I found them in a few locations, namely from:
~/.local/share/applications and
~/.gnome/apps I'm guessing they will be in the first one on elementary (I checked on GNOME).
Anyway, to know what ones you want to remove, select them all and open properties. Then chose More and Click Execute, next to Owner and next to Group. The number should now be 774.

Their icons will change from the unknown file to the app logo:


Then you can delete the ones you no longer want.