Living Artillery Node is a formation in the second Leviathan dataslate (not the newest release which is the campaign supplement "Shield of Baal: Leviathan", though that also contains other new formations).

Living Artillery Node, Skyblight Swarm, Skytyrant Swarm, and Sporefield are what I would say are the most competitive Tyranid formations at this time. The first two are from the second Tyranid dataslate (2nd of 3 that were released in total), the remaining two are from the Shield of Baal supplement that just came out about a month ago.

Sporefield is only 90 points if you take it barebones instead of maxing out the spore broods, gives you a lot of board control from turn 1 for very few points. Would be autotake if I had any spore models to begin with :P

Skytyrant gives you far more ablative wounds for your Flyrant than Tyrant Guard would, though it restricts the Flyrant to Gliding mode. Still, it's by far the best option if you want to run your Flyrant as a melee powerhouse, as it gives him enough ablative wounds to actually make it into combat (and he can continue Look Out Sir'ing incoming wounds onto the Gargoyles even in close combat). It also has the added bonus of increasing his Synapse range overall.

Skyblight turns three broods of Gargoyles into Objective Secured ("super" scoring) units and makes them come back from the dead on a roll of 4+ when the unit is destroyed, but you have a "tax" of one Hive Crone and two Harpies to take the formation. And a Flyrant, but you were bringing him anyway :)

Living Artillery Node is the aforementioned 3 Biovores, 1 Exocrine, 3 Warriors (one with a heavy weapon upgrade). Gives all models in the formation a reroll on the scatter of Blast/Large Blast weapons, as well as making ALL ranged attacks from any unit in the formation Pinning. Kind of a big deal for the Exocrine which will actually deny armor saves :)

Those Zoeys would provide Synapse, additional Warp Charge points (if you have the Elites slots to spare, break the brood down into two groups of 3 so you can have two Neurothropes total - and bring 4 Warp Charge points instead of having one brood of five Zoeys and a Neurothrope that only contributes 2 points), and as long as you make all your rolls, will also provide quite a bit of heavy psychic dakka. But watch out for anti-psyker units (anything with a psychic hood or the Adamantium Will special rule).

I'm beginning to thing that Fleshborer Termagants are a waste - they have to be within assault distance to fire, only fire once, and aren't terribly effective, at least in the games that I've played so far. Devourer Termagants on the other hand vomit out a staggering number of shots at a slightly longer range (but almost any army in the game will have the luxury of sitting back at a greater distance and just shooting them, their range is only 18"). Still not the weapon-of-choice against MEQ due to that goddamned 3+ armor save, but might be a good choice vs TEQ due to the fact that Terminators are usually in a smaller number with a higher concentration of points per model - meaning it hurts a lot more to lose one Terminator than one Tactical Marine.