why isnt this a thing? its a pain in the ass individually selecting them one by one

Add some, please! ^-^

I have only one question - what lvl of rare/epic/titan gear I must craft to get these gear with *set bonus*? Because there like 30, 50, 80 lvl gear and so on.

300 active is kinda meh

It's been brought up before, but more people will play if they are added. I understand it takes time to implement it and decide what should be an achievement, as well as a retroactive achievement unlock system. Just know that it'll definitely increase people playing. I haven't played in awhile because of that reason myself. Idle/Clicker Games without achievements feel like a drag....