Other than the Kamen Riders I know of only 2 tokusatsu heroes who's belts have anything to do with their transformation, most are just decorations.
Ch˘jin Baromu-1 (Superman Barom-1)'s belt holds "Bop" which turns into his car Machrod.
Henshin Ninja Arashi - Hayate's belt flashes during his transformation into Arashi. After the transformation the belt is different.
Hayate's twin brother Fuyute appears as the magical ninja Tsukinowa, whenever Arashi is in grave danger. His belt is just symbolic. There is no henshin sequence, Fuyute is never seen, only Tsukinowa.
Jinzo Ninge Kikaida - there are switches on the side which turn on the Sidemachine motorcycle's self stearing system otherwise the belt is just symbolic not a henshin device. The same belt is worn by Jiro and Kikaida.
Hakaida (Kikaida's "younger brother" and greatest enemy) - belt is just his symbol.
Robotto Keiji - Robot Detective K's belt flashes just before he destroys the Bad Robots. K was originally going to be named J (for Japan?) but it was changed to K before filming begun.
Kikaida-01 just 01's symbol, worn by Ichiro and Kikaida-01.