The Mine Pits in the Iron Range are awesome. Not sure if you can go to any of them anymore though. You used to be able to go to them without any issues, but from what I’ve heard they’ve started giving out trespassing tickets.
Duluth has Lester, Train Bridge, Ice House and a few other spots.
I’ve also seen people jumping at the Temperance River near the bottom of the main gorge; although, I’ve never jumped there.
I think you can jump at the waterfall at Tettegouche too. I’ve never heard of anyone jumping off Palisades Head or Shovel Point, it might be possible but I wouldn’t recommend trying lol, you’d probably die.
There are multiple places in the Boundary Waters where you can jump.
This video shows a bunch of places, several of which I mentioned.
https://www.newschoolers.com/videos/watch/1012564/2010-Duluth-Swim-Video