“Budget” means different things to different people, so it might help for you to provide a price range.
I have a Dell U2723QE that I’m pretty happy with. At $600, I consider it a budget monitor because it’s a lot less than the $1600 that Apple charges for a Studio Display.
(I would love a Studio Display but I can’t justify spending that much on a monitor. Plus, the U2723QE is nice because it essentially functions as a KVM switch, so it makes it easy to swap my webcam/keyboard/mouse with my PC.)