You can actually get a lot of Mitigative Logograms from the level 43 Fire Sprites at the southern aetheryte, but only if you didn't out-level them beforehand. It's how I stocked up on well over 100 of them and now have more Shell L and Stoneskin L than I will ever need. A similar case is true for Fundamentals, although I long since out-leveled those by the time I learned what lower level sprite dropped them.