How much Bluegleam is there to collect?
This article contains a extensive list of quest rewards and machine locations where to obtain Bluegleam. While the article states their quest list is incomplete, the very bottom of the page says
Hopefully between the quest rewards and open world Bluegleam formations this is all you need to know to collect all the Bluegleam you could ever need in Horizon Zero Dawn: The Frozen Wilds – it was enough for us to purchase all three Banuk weapons and the four new outfits, anyway!
(emphasis my own)