After doing 77 PvP battles, my results look like this:
- 51 Common Ingots
- 24 Rare Ingots
- 2 Ultra-Rare Ingots
Unless I’ve been very unlucky those three rarities are the only Ingots that drop from PvP. Even if there is a tiny chance to get higher rarities, those will be too scarce compared to upgrade costs to have any noticable impact. Technically, 1k Common Ingots + 10k Souls can be transformed into an Epic Ingot, which would make fully upgrading an Epic weapon cost 35k Common Ingots + 350k Souls. That seems to be pretty much the limit, higher rarities will have to obtained from other sources.