Cluster grenades would be awesome. They would explode after couple seconds so you can throw then in the air and it explodes releasing little exploding particles that explode on impact. They would be great for destroying landscape. You should choose grenades like weapons. If you like regular grenades then choose them, or if you like cluster grenades choose them. Please comment if you like this suggestion or tell what it needs more.
For those who does not know how cluster grenade looks, play some "Worms" :P