I'm sitting on 55/60 - with all the other triumph related ones completed - and I feel like the 5 remaining ones must be Dreadnaught secrets - such as Toland. That's going to be a chore I'd rather not do. Freaking Toland didnt even spawn in two of my last instances. Edit; Seems like I'm missing all the drifter ones. That's odd. Edit 2: Ok I totally missed the part where you simply visit the Drifter and it's in his inventory. I thought they were just related to hiim through some lore but had to be found like the rest of them - and the first one being the one right next time him in the Tower. Typical Bungie fashion to be as confusing as possible and put them on a NPC that no one ever visits. It would literally be impossible to complete 50 % of this game without the internets help.