When a numeric value appears above an opponent for the amount of damage you've done, and floats up slowly while fading out. Or when you gain XP, or earn money, or a myriad of other things. Is there a common name for this floating value thingy?
The name of that floating-up fading number UI thingy?
I've always known it as floating/floaty text. Not sure if this is an industry-standard term, or if such a standard term even exists, but that nomenclature seems to get the point across well enough :)
Call it whatever you like. Alert may be a good name?
You know the pop up messages you get when someone signs in to messenger or whatever? You know what they called that? Toaster pop up notification ;) They even have a system wide Toast mutex you should try and claim before you pop your own up (so you don't get loads trying to pop up at the same time).
Sometimes, 'damage indicators', but there's no common name, afaik.
[Edit:] No wait, 'damage indicator' is the screen-space red flash to tell you what direction damage came from.
If I remember correctly, in the Warcraft III World Editor (which lets you build your own mods to Warcraft III, e.g. DotA), Blizzard's programmers just called it 'Floating Text'. I think the name is general and descriptive enough.
The technical, generic name for rendering that thing is "billboard", which applies not only to text but to almost anything else that is 2D being rendererd in a 3D world, often oriented towards the camera regardless of the angle you're looking from (but not necessarily).
'billboard' is one implementation method that can used to display them in a 3D game, but the interface/design/concept is very common in 2D games too (going back many years).