Krieg has special melee formula that makes bladed weapons with him deal less damage than his regular axe swings at some point during leveling. I don’t remember when exacty it happens but at level 67 you might want to give a try to his regular melee as it might surpass the damage of them, even the law.
A level 50 fire or corrosive Pimpernel should be an effective killing tool some ways above 60. My level 50 slag one was 1 or 2 shotting enemies on good hits somewhere around 63 and that one didn’t even have an element to match the weakness. It’s still part of my loadout at OP2 for it’s slagging capabilities. The only thing I’d consider switching it for is a slag Snider and I haven’t ran into one.
If you pick up a bladed Rubi, especially a slag one, I’d throw that into the bank. A melee Zer0 might love it. While you probably won’t be shooting it much, if you get a Rapier in slag it might be worth keeping too.
The only other quest item I can think of is Sandhawk if you feel like doing some beehawking. As most of the damage comes from the bee and the unlisted projectiles on sandhawk it’s going to be very effective even if severy behind in levels. Just be aware that it’s going to be completely useless if you get hit by anything and lose the bee boost. I’m still carrying a low level fire one around for treants and tinder snowflake farming. I wouldn’t take it anywhere where I’m expecting to get hit though.