Does imperium have something japanese teisintai like? Like guardsmen with backpack full of explosives and meltashit and switch for booming them trained for charging enemy tanks, lances with explosive warheads for exploding enemy tanks with you, human guided torpedoes( with pilot inside), suicide trucks?
Some Rough Riders wield special lance weapons equipped with one shot tips, some explode like frag grenades, some have quickly burned out power fields, some have melta bombs built into them. I think there might have been a flame one, but I'm not sure anymore.
Suicide bomber units aren't really a thing in the Imperium, though some Penal Legions in the fluff do use suicide squads to tie up enemies in cqb then shell them with artillery. In general though most of that sort or role is performed by things like Arco-Flagellants, augmented and brain washed people with flails implanted into the remains of their arms that go berserk on command and fight until either they or their enemy is dead.
Human guided torpedoes, not exactly. There are missiles that contain a servitor to keep them on target, but servitors aren't really human anymore, given the lobotomy and augmentation.
Suicide trucks is a no to my knowledge. The Imperium considers technology far too important to waste trucks on suicide bombing runs. There are a lot of Imperial Guard forces that basically tank rush enemy positions with flamethrower/toxin sprayer tanks that do blow up on occasion, but that's not really the intent behind them.