They tend to recommend C:\Users\YOURNAME\Documents\Resolume Arena 6\Extra Effects . But you also need to set that folder up in Resolume -> Preferences -> Video.
This can really be any folder. But if you like to back up your shows, it is easy to also put your extra effects under the above folder. Then you can just back up the "My Documents" folder, or at least your Resolume folder and all your extra files will be in one spot. Just make sure to point Resolume to that folder in the preferences.
I actually though I remember that R6 was supposed to automatically look at that folder. I don't think that feature was added though.
They tend to recommend C:\Users\YOURNAME\Documents\Resolume Arena 6\Extra Effects . But you also need to set that folder up in Resolume -> Preferences -> Video.
This folder is always scanned during startup. This happens automagically, so you don't see it in the list.
Awesome, I can't remember why I thought I had to add it. At the time I knew that was supposed to just work. Either way it was not hard to add and a good fundamental lesson of using settings.