Does anyone know what kind of metal is suitable for bending into a trigger guard?

Anything you want steel, Alum, Brass. They well all work.

Trigger guard for what?

A trigger guard for my Nintendo controller. By the way this is a forum about guns.

Lazog,

Please forgive that silly ol' Leftoverdj, he was probably all confused-like and that is why he asked what sort of thingy you wanted to make a trigger guard for. But at least you straightened him out there! Silly ol' him was probably getting bogged down in little details like a make and model, or ever whether you wanted it for a bolt action 22 or making a replacement for a shotgun triggerguard....

However, specifics are usually better than sarcasm if you want a really educated answer.

Lasog,
I guess the key word to your question "bend" of the three metals mild steel suits that purpose. I usually have my triggerguard laser cut to shape then I finish with hand tools. By the way I agree with Markwhite. Mel