So what cheese nuggest have you stumbledd on so far?
Fire Dragons+Webwaystrike.... So you suddenly have a lot more points to spend since you don't have to take the wave, so why not take fulkl squad to pop that LoW turn 1 lol.
It depends on the Lord of War you want to pop. Moreover, point for point, 40 Guardians deployed via Webway Strike is a lot scarier than 20 Fire Dragons to most lists. Heck, you can take 40 Guardians and a Crimson Hunter for the price of 20 Fire Dragons w/2 Exarchs. Let's see how they compare against Marine stats. I threw in 3 Fire Prisms using Linked Fire just for fun; the Fire Prisms are only using their Prism Cannons in the following examples because I assume they're hiding at range and only exposing themselves one at a time to use Linked Fire.
vs. Marines40 Guardians + Crimson Hunter: 15.37 dead Marines, 31.32 pts/kill
40 Guardians: 13.33 dead Marines, 24.00 pts/kill
20 Fire Dragons w/2 Exarchs: 11.30 dead Marines, 42.49 pts/kill
3 Fire Prisms (Linked, Dispersed): 13.83 dead Marines, 34.71 pts/kill
I separated the Guardians to show how efficient they are at killing infantry. Over half of the work done by the Shuriken Catapults against Marines is from their rending, and when you shoot at anything squishier than Marines with the Guardians, it just becomes a blenderfest. Note that the versatility of the Fire Prism is roughly comparable to the combined arms of the Guardians + Crimson Hunter. On the other end of the spectrum, here's what happens when these units shoot a vanilla Wraithknight.
vs. Wraithknight (no Scattershield)40 Guardians + Crimson Hunter: 11.41 wounds, 42.08 pts/wound
40 Guardians: 7.41 wounds, 43.20 pts/wound
20 Fire Dragons w/2 Exarchs: 27.68 wounds, 17.34 pts/wound
3 Fire Prisms (Linked, Focused): 20.13 wounds, 25.31 pts/wound
As expected, the Dragons are excellent against big targets, although you still need two full squads to kill a Wraithknight (almost three full squads if the WK had a Scattershield, by the way). Yeah, there's a bit of overkill with the Dragons, but I'm not concerned about it, at least not enough to split fire from the second squad if I was trying to bring it down the Wraithknight in a single turn. Unfortunately, they're much easier to kill compared to 40 Guardians and a Crimson Hunter, and they don't benefit from Celestial Shield.
Despite only wounding on 6s, the Guardians are almost exactly as efficient at killing Wraithknights as a Crimson Hunter. Let that sink in.
Also, Fire Prisms are finally good! However, they require a CP and half movement every turn to be worthwhile. I used Focused instead of Lance because it's slightly better unless the Wraithknight was in cover, although the higher random damage of Lance could lend itself to more profitable CP re-rolls.
Having said all of that, the single scariest thing I've found with the new Codex is the sheer ease of alpha-striking, which has been the biggest problem in 40k for its entire history. Aeldari just happen to be even more amazing at it than usual.