just suggesting a few updates to this article, including naval units. it wouldn't let me edit. i would list the techs that unlock the units, too, along with which type they are.
cavalry, 15. military tradition, rifling.
tactics: flanking cannons and city attack.
counter: machine-guns, riflemen
grenadier, 12. military science.
tactics: riflemen
counter: cuirassier
cuirassier, 12. military tradition.
tactics: archery units, flanking cannons and city attack
counter: riflemen, pikemen, elephants
musketman, 9. gunpowder.
tactics: all pre-renaissance units.
counter: all post-medieval units.
infantry, 20. assembly line.
tactics: gunpowder units, e.g. marines.
counter: machine-gun
marines, 24. gunpowder.
tactics: machine guns and artillery; amphibious assault
counter: mech infantry, infantry
bombers, 16. radio, flight.
tactics: cities and stacks, resource denial, naval units
counter: fighters, destroyers.
fighter, 12. flight, combustion.
tactics: air superiority
counter: promoted fighters, destroyers, machine guns.
airship, 4. physics.
tactics: reconnaissance, submarine hunting
counter: fighters, destroyers, machine guns.
gunship, 20. rocketry.
tactics: tanks and artillery
counter: jet fighter, SAM infantry, mobile SAM
jet fighter, 24. composites.
tactics: air superiority
counter: promoted jet fighters, mobile SAM
mech infantry, 32. robotics.
tactics: city defence
counter: bombers, combined arms
anti-tank, 14. artillery.
tactics: tanks
counter: infantry
paratrooper, 24. fascism.
tactics: surprise attacks
counter: machine gun, infantry
tank, 28. industrialism.
tactics: city-raider, attack
counter: anti tank
modern armor, 40. computers, composites.
tactics: city-raider, attack
counter: gunship, panzer
stealth bomber, 20. stealth.
tactics: cities and stacks, resource denial, naval units
counter: promoted jet fighters
stealth destroyer, 30. stealth.
tactics: naval supremacy.
counter: stealth destroyer
submarine, 24. radio, combustion.
tactics: carry cruise missiles, hunt battleships, carriers and transports.
counter: attack submarines, destroyers, airships
attack submarine, 30. rocketry.
tactics: hunt submarines, carry spies
counter: destroyer, airship
destroyer, 30. combustion.
tactics: hunt submarines, air-defense, city-bombard
counter: battleship
battleship, 40. industrialism.
tactics: naval supremacy, destroyers
counter: air units
missile cruiser, 40. robotics.
tactics: naval supremacy, carry missiles
counter: air units
ironclad, 12. steel, steam.
tactics: pre-ironclad
counter: post-ironclad
ship of the line, 8. military science.
tactics: frigate, privateer
counter: ironclad
frigate, 8. chemistry, astronomy.
tactics: privateer
counter: ship of the line
privateer, 6. chemistry, astronomy.
tactics: caravel
counter: frigate
caravel, 3. optics.
tactics: trireme
counter: privateer
trireme, 3. metal casting.
tactics: galleys, barb defense
counter: caravel, galleon
galley, 2. sailing.
tactics: transport
counter: trireme
galleon, 4. atronomy.
tactics: transport, caravels
counter: frigate, privateer
transport, 16. combustion.
tactics: transport, pre-industrial navies
counter: destroyers, submarines, battleships
guided missile, 40. radio, rocketry.
tactics: bombard
counter: none?
tactical nuke,

. fission, rocketry.
tactics: bombard
counter: interception promotions, bomb shelters
icbm,

. fission, rocketry.
tactics: bombard
counter: SDI, bomb shelters