An Imperial Knight Paladin excels in engagements, where its Chainsword and Shock Lance will make short work of most targets. It is also armed with a Battlecannon for long range support.
The Necron Scythe Harvest Ship has powerful space-to-surface weapons capable of destroying the largest of targets. Two Pin-Point Attacks each provide D3 Titan Killer shots, and the NetEA list also adds an Orbital Bombardment attack for destroying and disrupting large numbers of smaller targets.
A Tyranid Carnifex is a terrifying walking tank, with huge Scything Talons that will slice through the heaviest armour. It is fearless, and will never run from a fight.