The rules for the Angel's Wrath Intervention Force can be found in White Dwarf 47. This formation is a relatively low investment, requiring only a Vanguard Veteran squad and two Assault squads. The squads all have to be equipped with jump packs but can be any size and have any equipment.
The formation has two special rules. Guided Drop means that the formation must Deep Strike, but all three squads arrive at once. The Vanguard Veterans deploy first as normal, but the Assault squads don’t scatter as long as they deep strike within 6” of the Vanguard Veterans. Meteoric Impact means that any enemy unit within 6” of the units within the formation take a S4 hit for each model within 6” of a model in the formation. Affected enemy units then move as if in difficult terrain for their next turn.
This formation is quite good at killing hordes of infantry. A small Vanguard Veteran squad can land pretty conservatively, and then guide the Assault squads in right next to enemy units, who will then take a lot of S4 hits. The Assault squads should be armed with flamers to mop up any survivors in the shooting phase. The Assault squads will be so close to the enemy that they will be in danger of assault next turn, difficult terrain or no. However, enemy units that don’t want to assault will have a hard time getting out of assault range of your units.
This formation is a great choice is you’re worried about hordes of enemy infantry. It won’t wipe out Imperial Guard blob squads or Ork Green Tides, but it will do a lot of damage for the points. I would take all three squads as 5 Marines strong, add one or two close combat weapons to the Veterans, and load down the Assault squads with flamers.
The downside to this formation is that it’s a formation. It can’t get Red Thirst, which would be useful if it survives to launch assaults after the drop. More importantly, it can’t benefit from your Warlord’s Descent of Angels trait, which would make this formation extremely accurate and therefore extra devastating.