[implements]

Also S.Q.L - but it’s an Initialism, not an Acronym (the latter being pronounceable as words eg NASA).

(Re Doom) To my shame “ID Software” was always I.D not Idd, though! - don’t know how common that was.

[sgt]

ID Software is "Idd" though, isn't it? That was recently confirmed by Tom Hall on Reddit. He came up with the name.

[Quikinterp]

I believe it is. And it's lower case as well!

[sgt]

id Software