I have farmed dragons and done just about anything I could to get my master rank up. I was starting to think I was stuck, then I noticed runcrafting. Rune crafting can give you all of the building blocks and weapon variants plus some tomes, it is also a good way to get your mastery rank up. You will need to be in a club or be able to get into U5+ worlds, the reason for this is you need to get into sky worlds. The main materials for runcrafting are found in skyworlds you need to collect Radiant shards and Crystallised Clouds, it’s best to farm in a team and go all in on evey Dark Heart dungeon you can find. You will also find Radiant Giants which drop Radiant shards and can also drop Radiant Caches which give a greater Radiant shard reward but can also drop blank scrolls and the Radiant steed mount.
I only started this around a week ago and have had to buy stacks of scrolls so grinding scroll dungeons and Loot collecting the recipes is also required. I am currently on level 3 of Runcrafting and have Maxed out standard, metallic and Glass blocks.