Asymmetry is more abstract than simply having heroes, so that's one reason why people don't talk about that as much.
So I'll just give examples of asymmetry from the top of my head. Yes, I have played most of these games, though some more than others.
Starcraft 1+2, we all know about that. Protoss have shields. Zerg have creep. Etc.
Warcraft 3, resource gathering was different for each. The asymmetry was buried more in the details of each race, and each race had a clear counter for each unit type for the other race's units.
Warcraft 2, the clearest asymmetry are the late game spellcasters between the two races. Otherwise fairly the same.
Dune 2 is the same, factions are the same except for the 3 unique units for each faction.
Tiberian Sun (Command and Conquer 2), sort of the same thing, mostly the same in the beginning, but then branches out differently to each specialty for GDI's armor and Nod's stealth. Nod cyborg technology in particular gave a cross between infantry and vehicular endurance, and was countered by EMPs. The asymmetry was basically conventional versus unconventional weaponry.
Command and Conquer 3 continues GDI armor conventional and Nod stealth unconventional, but the alien Scrin offers asymmetry by having a flying construction unit and mind control units.
Red Alert 2, Allies have chrono technology (teleportation), Soviets have iron curtain tech (invincibility), Yuri has mind control. Other different technologies like Allies are close enough to their counterparts to not be too assymetrical, but it was still a nice touch (for example, a Prism Tower and Tesla Coil are charged differently but still have the same result, a beam of something towards an enemy).
Red Alert 3, Allies have cryo tech (freezing), Soviets have armor, Empire had a different construction mechanic entirely. Other asymmetry is more in the details.
Command and Conquer Generals have USA with lots and lots of drones that accompany units for support repair and fire and helicopters for resources, China with propaganda, nuclear radiation, and hacking (resources), GLA with chemical warfare, suicide units, and tunnel networks and quickly rebuildable structures but no air units.
Grey Goo, the Grey Goo faction basically reproduces. The Mother Goo/constructor's resources is the same as its health and they can eat enemy units. Beta have hard points they can use as defenses and uses hubs to build bases. Humans have teleportation and power conduits that give them centralized bases. The Shroud can build anywhere unlike other factions but only have slow extraction of resources unlike the harvesters of the other factions but cannot auto produce units like other factions.
Universe At War, each faction plays almost completely differently: Hierarchy has massive crawlers that function as the faction's structures and could crush other units, Novus uses a network to teleport around the map, Masari could change its entire faction into Light mode (attack) or Dark mode (defense) and each mode completely changes the faction's gameplay
Age of Mythology, there are five cultures, Greeks acquire worship by villagers assigned to temples, Egyptians acquire worship through monuments and have healer units, Norse have two resource gatherers and generic heroes that can be produced en masse and gain worship by killing enemies, Atlantean villagers do not need to return to a building to increase resources and can upgrade their normal soldiers to hero units and their town centers acquire worship, Chinese resource gatherers can drop off all resources at a single site and have gardens that gain all resources passively and have only one infantry unit (with all other units being archers) and the only culture with amphibious units.
Age of Empires have a lot of civilizations that are different details such as unique units and buildings and statistics, but there are commonalities. 3's Asian Dynasties civilizations have Consulates that receive shipments. 3's WarChief civilizations share canoes.
Dawn of War has 10 full factions. There is no clear asymmetry with just the mechanics, however the feel of each faction is definitely different.
Company of Heroes have different progression for Allies versus Axis. Armored and specialized Axis has three phases while versatile Allies usually plop a Barracks then Motor Pool.
Warrior Kings starts you off as a neutral faction. But by choosing to build a Church, you pledge yourself to the Imperials, or if you build a Maypole, pledge for Pagans, or if do the neutral route in the middle with a Guildhall for the Renaissance faction. And you can have a part Imperial and part Renaissance mix OR a part Pagan and part Renaissance mix, but no Imperial-Pagan mixing. The asymmetry here is that Renaissance is for sieges and heavy upgrades, Imperials holy units can exorcise demons and call upon Acts of God, equivalent to superweapons , and Pagans can swarm with demons and other massed cheap units.
Civilization, each civilization is different in mostly statistics, but multiple victory conditions I believe offer the most asymmetry in a Civ game. There is a domination victory, cultural victory, religious victory, science victory, etc. So asymmetry is not limited only to factions.
Conquest of Elysium and Dominions series from Ilwinter Games have many, many factions for their strategy games that are almost completely asymmetric. They are balanced by making sure every unit has at least one hard counter *somewhere* in another race, not necessarily all races.
Endless series seems to master faction asymmetry in the 4X space. Each have different goals.
Dune board game factions had cards that had different effects on different factions, different victory conditions, and so on but have the same core gameplay.
Cthulhu Wars board game is the same, different victory conditions and yet even with same core gameplay, the factions play out very differently.
ROOT board game have completely different game mechanics for each player almost entirely. Some factions can't even transverse on the forests and have to be limited to the roads. Each player have totally different goals to win.
Among Us and other Mafia/Traitor games, there is an asymmetry between the Crewmates and Impostor. Both have almost totally different mechanics and tools, from doing tasks versus sabotages and killing. In other Traitor games like Salem, each player can have completely different roles and thus tools to win.
From that we get types of asymmetry:
Mechanical asymmetry - Games with players and factions that have completely different game mechanics from each other are probably my favorite.
Economic asymmetry - Players and factions that utilize the same resources differently and gather those resources differently. Age of Mythology shines in this.
Movement asymmetry - Factions that utilize different locomotions. For example, a faction may have air units and another has naval units but none for other factions. Another faction may have hover for their vehicles, making them able to cross water, instead of tracks. Factions that can teleport versus those that have no teleport is another example.
Weapons asymmetry - Players with specializations on different weapon types. For example, a melee heavy faction versus ranged faction. A siege faction versus a defensive faction. And weapon effects, too, for example, a piercing railgun that hits multiple enemies in a line versus a poison cloud that hits multiple enemies in a circle. You can have the same unit types but giving each a different weapon effect changes the battlefield completely.
Upgrades and technology asymmetry - Rare to have alone because it is not so impactful visually, but you can have the exact same units and everything but with different focuses on upgrades, such as more attack or more defense.
Unit type asymmetry - Sort of related to weapons asymmetry but more deliberate and wider. For example, an infantry heavy faction versus a vehicle heavy faction. It could even take the form of a faction with no heroes versus a faction with heroes.
Base Building asymmetry - This can take on the form of things like mobile structures like in Starcraft, limited construction areas like creep, or even different construction mechanics like Empire of the Sun nanoconstructors versus the traditional MCV of Allies and Soviets or a hub system versus a network system in Gray Goo.
Objectives asymmetry - As mentioned, Endless and Civilization has different victories, Among Us crew and imps have different goals. This is often paired with mechanical asymmetry but not always. Because of different victory conditions, players play differently.
Progression asymmetry - This is often tied to build orders. Company of Heroes has Allies with fairly straightforward progression, whilst Axis have three phases of progression. So mixing up things is an asymmetry, for example, a faction may get light vehicles before they get infantry, or aircraft before they get tanks. Rocketeer infantry/jetpack infantry rush is an example for Red Alert 2/TibSun for the latter. This is only progression and not unit type, for example, you can have two factions with the same exact units but different progressions, forcing a different gameplay.
Feeling asymmetry - You can have no mechanical asymmetry and have the same core gameplay mechanics but still a different feeling for each race by just having different stats. For example, heavily armored faction versus a stealthy hit and run faction are often popular archetypes. Or a melee heavy faction versus a ranged heavy faction. Same mechanics, different stats, different feels.
Map asymmetry - Or you can have no faction asymmetry whatsoever, and just have the map be asymmetrical. For example, a map with a different resource for each side.
Which asymmetry do you like? Which asymmetry do you not like?
