4:3 aspect ratio
16:9 aspect ratio
16:10 aspect ratio
5:4 aspect ratio
Automatic wide aspect ratio
Aspect ratio: automatic
Anamorphic
Letterboxed
Widescreen
Customizable aspect ratio
Customizable anamorphic aspect ratio

Common resolutions: 320x200, 640x480, 800x600, 1024x768, 1280x960, ...
Ratio-to-one: 1.‾3:1, 1:.75
Max end resolution at UVL: 800x600

Although considered "standard" aspect ratio on PC platforms, some games allow you to set other aspect ratios and therefore support for 4:3 aspect is good idea to note (otherwise, how'd you tell it also support 4:3 in addition to widescreen and others?). There are also games that do not limit the available resolutions in any way - they query the system or hardware what it supports and lists all that without giving it much thought - which may give the illusion that they support more than just the basic 4:3 aspect ratio but in reality do not, a problem most prevalent in some older 3D games before widescreen monitors started to come to regular gamers, and some may have not even thought about it (even now when many have them).