Common Agricultural Policy - gone
State Aid rules (sort of - seems to me there are still competition mechanisms in place under the post-Brexit arrangement which could be acted on - a very much untested)
Breakup of the union (bit of a stretch to include here though tbh, its not reliant on Brexit at all, though is accelerating it now)
"Not being part of an apparently ever closer political, economic, diplomatic and military union" is a really good one, though it is far from certain what the near future of the EU is . Good reason to believe it is going to continue to centralise.
A layer of unelected bureaucracy has been removed, and a bureaucracy with a neoliberal agenda and power at that.
Its got to be good for democracy.
On immigration we now have a classist points based system. I hate it with a passion, but many pro Brexiters love it, and would say it is a positive outcome