Games

I'm presently replaying Command & Conquer Red Alert 3 and love it. The cast for the FMVs is all-star, the game itself is a super refined version of Red Alert 2 (itself an all-time classic) and the story has no bearing on the rest of the series so it can be played in isolation with no advance knowledge of C&C

Metal Fatigue. It's like what a Gundam RTS should be. It's awesome. If I were a billionaire I would remake it.

It's not real time but Civilization is a must for any strategy fan. I personally recommend getting V and all its expansions, it's peak for me still. Some like VI but I could never get into it.

For old school RTS, Total Annihilation or if you fancy something a bit different then The Settlers II (Pioneers of Pagonia is a more modern remake). I grew tired of RTS and moved on to turn-based but Stellaris is one that recently drew me back in.

For tactics I'd say Advanced Wars, Fire Emblem and Disgagea are decent shouts. Into The Breach is probably my favourite indie of the genre, a lot of strategy packed into a small game.

If you like turn-based then Civ has always been top of my list.

RTS: Zero-K

RTT: Steel Division 2 and Warno

TBS: Dominions 6. Songs of Conquest if you want a modern casual HOMM3 clone.

TBT: Battle Brothers and Field of Glory 2

Grand Strategy: Basically everything from Paradox. Victoria 3 is my current favorite.

Warcraft and StarCraft. StarCraft 1 is free and the first campaign of 2 is free as well.

Others are Command & Conquer and Age of Empires.

Beyond All Reason maybe?

cracktorio

If you want to try an RTS that does something different, check out Against the Storm. It's an RTS, but there isn't an "enemy" so to speak. Instead, you are 'fighting' against the environment, trying to solve your economic and social problems before you are overwhelmed by external factors imposed by the level you are building on.

The game continues to evolve as your understanding of its various systems grows.

I'm getting into the Dominions series, recently picked up Dominions 6. You take control of a faction and try to spread your pretender gods influence enough to ascend to be the one true god. Combat is auto resolved but you can watch the combats and the mechanics are very detailed. I made a god that was a sentient glyph that bestowed fire resistance and flaming weapons on my faction of desert dwelling spider riders. Another time I was a sentient fountain of blood with innate abilities to raise an army of mindless skeletons so I could stack troops in masse.

Its a little clunky in the interface but once I learned what did what it because very engrossing

Command and Conquer Generals: Zero Hour.

I mean, obviously play the Red Alert games too. But Generals: Zero Hour was BIG fun in the day. A bit hard to get it to play nice with modern computers, but it was recently added to Steam so its at least legally acquirable again.

Age of Empires 2, obviously. Still the GOAT of Age. Its latest released still gets updates, which is great.

IDK about it being a "must play," but I actually quite enjoyed the strategic/tactical RPG Tuned Hearts, for the Japanese PC98 series of home computers. Im not much of a fan of turn based games in general, but something about Tuned Hearts kept me playing. IDK if it was the battle art or the hilarious enemy characters, but either way I enjoyed my time with the game.

The PSP had Joan De'Arc, which I think is based on an anime, but I could be wrong. It plays similar to Final Fantasy Tactics or Fire Emblem, I think. Not a bad little game.

For 4X, I like playing Stellaris. Granted, every time I play my saves get massively bloated and end game lag is unbearable sometimes due to fleet sizes, and the developers update the game so often that either my save breaks or the systems are vastly different from whenever I played last, but aside from that the game is a lot of fun. If a real time 4X strategy space civilization game sounds interesting to you, I'd give it a shot. Otherwise for turn-based, Galactic Civilizations III from Stardock was my go-to.

The Homeworld series is great with fantastic campaigns (minus Homeworld 3 I've heard, not even played that).

I'll also throw in a classic Imperium Galactica 2 because I still think for a 90s 4X RTS it has so many elements that I've just not seen replicated since. Though usually short and quick, it has fully simulated and controllable space and ground battles; espionage; diplomacy; you assign your unlocked tech to hard points on your ships... It's Stellaris but better in most ways, imo.

Knights and Merchants 😉 Older classic, but there's a remake that makes it more playable on modern machines