The best vigor/large shard farm I like to do is in the Empyrean - plant a seed right by the boss arena, then farm the two twins on the right by the steps. They are weak to wither so I use Barrage of Echoes and they go down quick. Depending on the runes and rings you're using, you can get almost 1k per run and tons of large shards. They also drop their weapons and armor so you can sell the extras and get a lot of vigor in just a few minutes. You can also get some plucked eyeballs since folks seem to die to those twins a lot.