Helmet Manipulation – The helmet, and/or other type of headwear, allows the user to accomplish superhuman effects.
The Unicorn (Marvel) has a helmet that can fire various types of energy rays (Official Handbook of the Marvel Universe V2 #14).
Wizard (Marvel) has a helmet that allows him to control his body armor with mental commands.
The Helmet of Fate (DC) provides the user a vast array of magical powers (The Immortal Dr. Fate #1).
Ant Man’s Helmet (Marvel) allows him to communicate with ants in Marvel Fact Files #31 (Eaglemoss).
The Wasp (Marvel), the Nadia Pym version, uses her helmet uncharacteristically as a throwing weapon in The Unstoppable Wasp #4. I have to assume the helmet is just a helmet and not a cybernetic helmet with which she can control ants otherwise her move is pretty stupid. Having ants attack an opponent is much more effective than hitting them with a helmet.
Brain Storm (DC) has a helmet that can absorb stellar energy and gain various mental powers.
Crazy-Quilt (DC) has a helmet that enables him to see and emits blinding light in DC Who’s Who V1 #5.
Serpent Crown (Marvel) gives the user a wide variety of powers but generally the user is controlled by Set (Official Handbook of the Marvel Universe V2 #19).
Menthor wears a helmet that gives the wearer psychic powers in T.H.U.N.D.E.R. Agents #3 (Tower).
Trading Card Games offer a wide variety of helmets and hats magical and mundane.
Crimson Felt Hat
Golem Skull Helm
Hat of Fire
Helm of Fire
Helm of Obedience
Helm of Possession
Helm of the Ghastlord
Helmet of Ten Storms
Helmet of Theron
Helmet of Yizo
Star Wars – AT-AT Helmet
Star Wars – Mandalorian Helmet
Star Wars – Rebel Assault Helmet
Star Wars – TIE Pilot Helmet