Most gels are fine, even if they say the maltodextrin or glucose is from wheat, it's so highly processed at that stage there's no gluten.
Endura energy bars and rehydration powder are fine.
Torq bars have oats in them, so it depends on your position on oats (around here it's 'if in doubt, don't eat it'). The Torq rep swears there's a coeliac on the Torq team that eats them ok, but my +1's not prepared to risk it.