Do Menagerie.
3x Normal - You get a mod with each of your first 3 completions. Can't remember if it's guaranteed or high chance, but there is no duplicate protection.
After that, do
1x Heroic - I think you're guaranteed a mod you don't already have on your first clear.
Do that for each character you have. I may be off since it's been awhile since I did it, but that's how I got all mine. You don't have to do the raid to get the mods.