Go to the place where the boss bloodwing was in the mission wildlife exploitation reserve and it will spawn The Mother Rakk, it's a giant rakk. it's not very hard to kill. Can drop rare loot, but no idea if it drops any legendary though. There is Savage Lee which you can find in three horns Divide living among bullymongs and he has a chance to drop that Unkempt Harold, which is by many players considered to be the best pistol in the game. There is Scorch in Frostburn Canyon, could drop Hellfire legendary SMG. There are loot midjets that can be found in many maps through the game, but if you don't finish the mission Doctor's Orders there will always be 2 loot midjets and 2 loot midjet robots in the 4 small boxes in wildlife exploitation where they run experiments on skags. They can drop many legendaries. These aren't really rare but they are hard to find. Except for Scorch a side quest leads you to him. Good luck :)
The Vault Hunter's Relic only drops the chances of white item drops by 5% and then splits that 5% between the green and blue drops. so say if the odds of drops are:
No drop:40%, white:30%, green:15%, blue:10%, purple:5%, orange:Only on named & bosses (and often about 1% or less there) OR 3 borderlands symbols on a slot machine (about a 1 in 5,000 chance)
The Vault Hunters Relic would only make that:
No drop:40%, white:25%, green:18%, blue:12%, purple:5%, orange:Only on named & bosses (and often about 1% or less there) OR 3 borderlands symbols on a slot machine (about a 1 in 5,000 chance)
assuming those numbers were accurate (the orange is pretty close but the others I am mearly speculating) then even if it were modded to be a 30% better chance (thus eliminating white drops all together) it would still only be about: None:40%, White:0%, Green:38%, Blue:17%, Purple:5%, Orange:special.
No modding of %'s will make the Vault Hunters Relic really worth wearing once others become an option. Better to wear a relic that works to improve your strengths (such as an elemental boost on a siren or a brand-specific relic that helps boost your best weapon) or compensate for a weakness (+shield capacity or max health if you find yourself dying too easily).
Best Answer
There is no new legendary items unique to the DLC, only some blue and purple rarity items. And regarding the Seraph crystals, they no longer drop on normal/TVHM, only on UVHM.
Both raid bosses hyperius and master gee have chance to drop variety of legendaries from the main campaign and some seraph items.
Generally the Sandhawk and Rapier are the only worthwhile items on the DLC and they are both easily obtainable by just playing through the dlc. Leviathan's lair has a pretty good chance to drop great relics and mods.