First up is the Bioblast Node, which consists of a Warrior Brood, 3 Carnifex Broods, and 1 Tyrannofex. The Warriors must include a bio-cannon, and each carnifex in the formation must also take a bio-cannon. The formation has the Split-Fire USR and when within 12" of the Warrior brood, re-roll 1s to wound in the shooting phase. Strong.
Next is the Wrecker Node, which is a Warrior Brood and 3 Carnifex Broods. Neither unit can take Bio-Cannons. The carnifexes in the formation deal D3+1 Hammer of Wrath hits, and re-roll 1s to Wound in the assault phase when within 12" of the warriors.
That is followed by the Tyrant Node, which has a Hive Tyrant, a Tyrant Guard Brood, and a Venomthrope Brood. The Tyrant guard must be 3 models and the Hive Tyrant cannot take wings. The hive tyrant in this formation adds 6" to its Synapse Range.
Next is the Subterranean Swarm, consisting of a Trygon Prime, a Trygon, a Mawloc, and 3 Ravener Broods. All units must start in reserve, and only a single reserve roll is made for the entire formation. The Trygon Prime deep strikes normally. The three Ravener Broods then emerge anywhere wholly within 6" of the Trygon Prime.
The final formation is the Living Tide, which is a formation of formations consisting of 1 Tyrant Node, 1 Synaptic Swarm (from Rising Leviathan II), 3 Endless Swarms, 1 Wrecker Node, and a Skyblight Swarm. They get all their formation rules and get a few bonuses. While the Tyrant Node Hive Tyrant is alive, all synapse creatures from the formation add 6" to their synapse range. You can also reroll all respawn rolls for Termagant, Hormagaunt, and Gargoyle broods.
So, that final formation is, at minimum:
- Hive Tyrant
- 3 Hive Guard
- 1 Venomthrope
- 1 Tyranid Prime
- 21 Tyranid Warriors
- 90 Termagants
- 90 Hormagaunts
- 3 Carnifexes
- 1 Flyrant
- 2 Harpies
- 1 Crone
- 30 Gargoyles
That's, with no upgrades, 3090 points, and comes with some serious bonuses.
Of the formations in this dataslate, Bioblast might be the best, but I would still prefer living artillery and skyblight. I believe those are the two best options so far. Subterranean could be good if only in that you group 6 units into a single reserve roll, guaranteeing you will get too many options deep striking at once for your opponent to handle well.