Which dragons go in a Spearmen, Archer, Cavalry or Shield army?

To cash in the +20% affinity, build an army where all 3 dragons are green for the chosen type. The 🟢 dragons per troop:

• PIKEMEN (9): Crimson, Vaeldra, Jagadrix, Caraxes, Rhysarion, Syrax, Bevlorin, Dawnseeker, Venator.
• ARCHERS (10): Crimson, Seasmoke, Zivern, Daemoros, Tashix, Solstryker, Syrax, Arrax, Antares, Vhagar.
• CAVALRY (9): Seasmoke, Kalspire, Caraxes, Feskar, Malachite, Shadowsong, Thunderstrike, Shimmer, Arulix.
• SHIELDS (10): Kalspire, Malachite, Rhysarion, Velar, Arrax, Shadowrend, Nyrena, Vesper, Venator, Vhagar.

Also pick the type with the counter wheel in mind (your type beating the enemy's). Spearmen is often the best axis, because it lines up several centrepiece dragons at once.