(assuming atmosphere)
(Rechargeable) Type A:
Basically a flashbang on crack, it releases several pulses of light, including any light that could realistically be used optically, (~between microwave and X-ray). The higher frequency light is in such a concentration as to be a little worse (damage wise) than a chest x-ray. If a flash grenade is broken, or otherwise improperly triggered to release its contents, major damage may occur in the path of the light if released through a small opening, such as a puncture.
(Detonation) Type B:
Pretty much average grenade. An approximately 9 foot diameter bubble of plasma is produced for <1 second. This grenade is a double whammy, as infrared radiation causes air to heat up rapidly, causing explosive expansion, then as it rapidly cools on loss of energy input, implosive contraction.
(Rechargeable)Type C:
Similar to a radio/radar jammer. Microwave through long radio wave frequencies are emitted, causing disruption to many methods of communication.
All laser grenades utilize the strange ability of light to form something akin to a crystal. It’s really quite strange to us, but ever since it was made practical by Varalthian engineers six thousand years ago, solid light based technologies have flourished.