Steel Rain DLC has added 7 trophies for Killzone 3.

Highly Decorated – Unlock Ribbons
Unlock all Ribbons in a single match while playing Operations or Warzone

Jetpack on Exo Action – Destroy Exoskeleton
Destroy an enemy Exoskeleton with your Jetpack while in flight in The Junkyard

Exo on Jetpack Action – Kill a Jetpack
Kill a flying enemy Jetpack with an Exoskeleton in The Junkyard

Deadly Threesome – Triple Kill
Get a triple kill while playing in Stahl Arms

I See You – Minigun a Marksman
Kill a Marksman with the Mounted Minigun in Stahl Arms

5 for 5 – Lots of guns
Kill 5 enemies with 5 different primary, secondary, or explosive weapons in a single match

Jack of All Trades – Kill all careers
Kill one enemy of each career type in a single match