Most Undertale fans have heard of Doctor Gaster, and if you haven't, all you need to know is that he can be spoken of by altering the game files (which I don't suggest doing).

The most commonly accepted form of Doctor W.D. Gaster is, in the game files, called "Mystery Man," so we don't actually know if that's him.

Now, onto his name.

The "W.D." is said to stand for "Wing Din" as in the font "Wing Ding," with his first name containing the "g" in "Wing," leaving us with "Aster." Aster is a font, as mentioned in fact ten.

Wing Dings are more of a language then a font type. They are used in the game when accessing a file that contains Entry Seventeen in Alphys' secret lab. This is supposed to be written be Doctor Gaster.

So, since his name is a font type, he is expected to be related to Sans and Papyrus. But that, my friends, is for tomorrow.