Our favorite Bulgarian arms manufacturer has added two new exotic grenades to their 2012 line up. The RLV-AD (Anti-Diver) round is designed to explode at a depth of 5 meters creating an underwater shockwave that is lethal at up to 15 meters and harmful up to 30 meters. The round is compatible with many NATO 40x46mm grenade launchers including the popular 6-shot Milkor MGL (some older launchers with short chambers could have problems chambering the longer exotic rounds).
The Arsenal RLV-TB-AD contains 100 grams of a thermobaric compound called TBC-2. Upon hitting the target the compound is dispersed into the air, creating an air-fuel mixture, then ignited. These grenades are said to be very effective in small buildings and caves. This grenade is also compatible with most standard NATO launchers.
The Pentagon got quite excited about the XM1060 40mm Thermobaric Grenade they developed at Picatinny back in 2003 or 2004, but I have not heard any news about it since.
[ Many thanks to Lionel for the info and photos. ]