MONITOR

This is the easiest part, choosing which panel will go with your system. You should already have an idea of what kind of monitor do you want but this is completely up to you, just keep in mind that 4K monitors require more horsepower.

CURVED OR NOT

There are many types of monitors but the recent innovation in these are the curved monitors. They are curved to create an illusion of a straight square image, also making it seem larger than they are. They can be confusing at first but you get used to the curvature in no time.

TN, IPS, VA, OLED

You might not know these but there are multiple types of panels for monitors and you might have noticed this. TN panels are those types of panels that distort the image when looked at from to the side or above, VA panels don't do this and typically have 3 times the contrast ratio and OLED has infinite contrast but it is barely being adopted by monitors.

WHAT RESOLUTION SHOULD I PICK?

Now a days the minimum you should get is a 1080P monitor, but you can easily go with something better like 1440p or if you really want to future proof your system you can go for 4K but keep note that games tend to run very slow on 4K resolution. Choose according to what your eyes tell you, for example I don't see the difference between 1440p and 4K but 1080p is noticeably blurry to my eyes.