Repair Kit:
A kit that when used repairs the player.

Mine:
Depending upon the armor,the mine is different. Each has it own subtle ways of eliminating the enemy.

Grenade:
Depending upon the armor, the grenade is different. Each has it own subtle ways of eliminating the enemy.

Beacons:
Targeting Beacon -- Allows you to set targets for your team for location or for destruction

Booster Beacon -- Boosts the player quickly across the map, Assault Only

Shield Beacon -- Adds an extra line of defense to the Juggernaut.  Last 10 seconds.

Cloak Beacon -- Cloaks the Infiltrator armor for when they need to get in quickly. Last 10 seconds.

Contact Reactive Armor:
Scout -- Steals ammo and health kits from the enemy on contact.

Stryker -- This armor cloaks on contact with an enemy, it only last for 5 seconds.

Infiltrator -- This armor blinds the enemy on contact.  You can then run and hide or shoot to kill.

Assault -- This armor has a special charge that knocks the pack off of the enemies back.  Watch out Nuke Bombers.

Engineer -- Sometimes the engineer doesn't have time to run around with a repair gun to help all the players.  On contact this armor will repair teammates only the same rate as one health kit.

Eruptor -- Well simply puts, knocks the enemy way out of the way.  Kinda fun if you like to shoot skee :).

There are no contact features for any of the heavy armors.  That would just be totally unfair.