There aren't going to be any original one-word gamertags available. You're probably better off creating words for your tag ideas. It's pretty rare to even see a real one-word tag that isn't something really stupid like Unconformities or Exploitings. Try taking some words and flipping some letters around in a way that its an original name and makes sense. My friend just recently created the gamertag 'Enfus' which isn't a word but looks really nice.