For Windows users, I can recommend ClickMonitorDDC[1]. While the UI is a bit cluttered, it has a neat feature:
You can display the current brightness in the notification area, hover over it with your mouse, and use the scroll-wheel to adjust it. I really like it.
I actually think I tried this one yesterday, and from memory it spammed my traybar with about 12 different icons. The UI isn't just cluttered, it's odd!
Still, it's a nice demonstration of what you can do with DDC, and just about anything is better than the crappy physical controls on monitors.
you can disable them in the settings. it gave me icons for brightness, contrast, saturation, and volume. I only care about setting brightness so I disabled the others
