I know not everyone will have these troops, but my counter for the true shot/undead teams is
Centaur Scout - to tank while the others mana up
Crimson Bat - true damage not dependent on skulls
Soothsayer - to power up the true damage dealers
Hero/Crescendo - true damage ignoring skulls
This has the advantage of dealing almost as much damage as a real true shot team, but is not dependent on skull generation and also skirts the current agile glitch. I only use it for invasions, not defense.