As I recall, the TIE/ln (basic model in ep.IV) had Black 1, Black 2, etc. -- those were the designations of Vader's wingmen in the DS trench run. The TIEs modified to work in atmosphere (can't remember their model type) which chased the Falcon on Bespin were Obsidian 1, Obsidian 2, etc. I think there was some thing about the <cough> TIE Defender </cough> where they were Onyx 1, Onyx 2, etc. So, for colors, I guess they just use different words for 'black' - get out your thesaurii!
I can't remember where, but the TIE Interceptor had an 'Avenger' squadron (Avenger 1, etc.). It may have been just a squadron sent out from the ISD Avenger. In the SW:CCG, there were also Saber, Scimitar, and Scythe squadrons. Types of knives seem to be a theme.
I suppose you could give the Rebels 'colourful' squad(ron) names, and Imperials things like blacks and greys, maybe. Unless there's some EU 'Gray Squadron' that I haven't heard about (probably Rebel/Republic or Imperial Intelligence group?). Supplement those with things like Avenger, Cutter, Crusher, and other destructive/violent themes, and you've got lots of names available.
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a.k.a.: Grandma Tarkin // hQ.Terrorek
Today's spelling/grammar tip: There = a (sometimes conceptual) place. "There is my car." or "There is such a thing as magic." // Their = posessive. "Their meat is full of worms." // They're = contraction of <they are>. "They're crazy!" // "They're trying to put their shoes up there."