I was just wondering, those are only gears, low level l, so actually I guess they should be still in game somewhere to be looted? Or inside old locks?

Im mainly interested about the blue founder set, if I remember well there are 2 sets, lv 16 and 21 or 23? Where do they come from?

But feel free to extend this topic to all old rare items and where they can be looted:

Bosses, mobs or locks?

Sry for grammar typos :v