Legendary stratagem uses

In a tournament a couple of weekends ago, one of our local Eldar players made a brilliant turnaround of his game with stratagems.

His Avatar had just been slain in melee by the first of two Blood Angels Dreads that had assaulted it. So he used 'The Avatar Resurgent' to bring the Avatar back to life, interrupted the fight phase to swing next, killing one Dread, and then a command reroll to finish off the other. Needless to say that was a fairly emphatic swing in the game, which led to an Eldar win.

What other game turning stratagem combinations can you see from the Craftworlds Codex?

One that occurs to me would require a Ynnari D-Scythe Wraithguard unit (along with a Craftworlds detachment for the stratagems).
Use 'Webway Strike' to deep strike the Wraithguard potentially backfield near two tasty targets
Have a Warlock conclave cast quicken for the extra movement (potentially using 'Seer Council' to get the power off)
Use 'Concordance of Power' to reach the Wraithguard from across the table
D-Scythe down one unit and soulburst onto a second

I used "Lightning Fast Reactions" on an Alaitoc Autarch Skyrunner with the Shimmerplume of Achillrial recently to hilarious effect.

-2 to hit him (-3 if more than 12" away) resulted in a situation where he absorbed an entire turn of shooting from most of an Astra Militarum army, then 2 rounds of melee combat. 6 command points spent (with 1 recharged from the Autarch ability) and I had the run of the table while my Autarch held off the enemy army.

"Forewarned" and a Dark Reaper blob will wreck your opponent's first turn plans, especially if they haven't come across it yet (got to use it several times at a double tournament last weekend- soooo much fun; soooo many delicious, delicious tears)