I will type only maximum simplicity stacks, that are very strong late vs "shades and dragons" (Strong range and melee A.P. or monstrous fast and strong melee A.P.)
Campaign only! And stack that "strong all around" - practically unbeatable, so can kill everything that you can encounter in campaign at any point. And ambush and map resistant. (So, mass artillery, mostly, is not an option.)
The empire - only demigryph knights (halberds).
Dwarf - no such stacks, sadly!!
Greenskins - only arachnarok spiders.
Vampire counts - can be either blood knights (but I do not like their head and helmets) or hexwraiths.
Warriors of chaos - dragon ogre shaggoths.
Beastmen - minotaurs (great weapons).
Wood elves - waywatchers (but have so-so head models, just like blood knights).
Bretonnia - only royal hippogryph knights.
Norsca - war mammoths.
High elves - sisters of Avelorn and star dragons.
Lizardmen - feral carnosaurs or ancient stegadons (both are not optimal because of rampage or low stats vs large).
Dark elves - shades (greatswords) or black dragons.
Skaven - hell pit abominations (but still poor compared to other factions' top monsters).
Tomb kings - hierotitans (but somewhat weak to mass range A.P.) and necrosphinxs.
Vampire coast - death shriek terrorgheists.
Just a reminder. Why, for example, not warplock jezzails for scaven? When ambushed by strong and fast - they die. Vs 20 dragons - they die. Vs close to 20 shades (huge dps and invisibility untill too late) - they die. Same for doomwheels or plagueclaw catapults, which can kill thousands of chosen in usual battles but will die vs dragons and fast and strong monsters.
Maybe you have some kind of super-stacks that can be strongest all around, and fear no ambushes, for any factions?