Frag Grenade
The standard explosive grenade. Useful for clearing out groups of enemies, flushing them out of cover, or destroying light vehicles. Can be cooked for precise timing. Always carry a few for emergencies.

Smoke Grenade
Creates a cloud of smoke, obscuring vision. Excellent for breaking line of sight, escaping detection, or providing cover for a tactical retreat or advance. Can be used to bypass heavily guarded areas or revive teammates in multiplayer.
Flashbang Grenade
Temporarily blinds and disorients enemies, making them vulnerable to attack. Useful for initiating an assault on a group or escaping a difficult situation. Less effective against Ceph.
C4
Remotely detonated explosives. Can be placed on surfaces or enemies and detonated at will. Great for setting traps, destroying objectives, or taking out vehicles. Requires careful placement and timing.