I no longer have LCD4. It was sold to fund Susvara. I still miss it sometimes.
When I had it, these amps worked very well with it:-
Oblivion - very spacious and airy. Helps LCD4.
Auralic Taurus Mk2 - similar to Oblivion but not as good.
Violectric v280 - if you like it creamier, nothing wrong with it.
Schiit Mjolnir 2 - by the time I had LCD4, MJ2 was sold but it would have driven LCD4 well too but tonally I prefer the above 3.
Wa22 - will work with LCD4 if you don't mind turning up the volume knob to 2pm. Nothing wrong with that. Why get full power but just use half of it, my amp builder would say. For headroom you say? Well it's either it has power or not to drive it.
As a matter of fact, if you don't need to blast, WA22 will even drive Susvara. I was showing this to my friend 2 days ago before selling the Wa22 to him. Now that will help (and He1000se) fund Abyss 1266 TC or a Telemachus (300b) amp. Gawk, I hate this hobby.
Ah I forgot... I had Burson Soloist 3xp. This will drive LCD4 very well too. Actually was a pretty good combination.
Lastly my Odyssey (KT88 / EL34 amp) drives LCD4 beautifully.