There won't be any links to YouTube videos or screenshots of games I'll mention but you will find them in both GOG and Steam. Here they are:
1. Operation Silent storm, best decribed as "Jagged Alliance 2, but better in gameplay". You can destroy almost everything with explosives; your soldiers can retreat AND watch in the direction of his last encounter with the enemy; you can shoot in the direction of an enemy you hear (there is a special icon for that) and if it so happened he is above you, you can make him fall and get injuries (which there are many); there is one thing that is abcent in this game but is there in JA 2 - interactions between your soldiers (which is a bit of a shame - there are possibilities for it). Setting - World war 2, most weapons are from that era (with the exception of panzerkleins and some lazer guns); you can choose both Allies and Axis as your faction, some of the missions will be the same for both sides, but most of the time even if a place of operation is same for 2 factions they are still played differently. There are six classes with their own set of skills, they also specialize in different areas (scouts are good at concealment, grenadiers are obviously good at throwing grenades, snipers do their best with sniper shots, etc.). On a side note - I am not certain that's still the case, but when I played Steam version 3-4 years ago there was no possibility to finish the last mission because the final boss just flew away and never returned so it is better to ask in the forums if it was fixed or not first.
2. Ground Control 2: Operation Exodus. Real-time strategy, mostly for the single player experience since there is only 2 factions to play in multiplayer (totally forgot it never had a proper multiplayer via Internet, only via LAN). The story is quite generic (but considering all of the stories and turns in them are already known, that is not a disadvantage for me) - we are a bunch of people from the space colony that decided to separate themselves from our metropoly, Terran Empire; we come through some successful battles against the Empire but then at certain point they show up with aliens named virons and there is only one solution left - to escape into unknown regions of space. Speaking of features in this game - every unit has 2 ways of operating (sometimes entirely different - for example, light infantry most of the time shoots with bullets, but in an alternative mode they switch to rocket launchers) and in case of virons there is a possibility to make entirely different unit by merging two of one type; there are ways to spend extra resources - you can make your dropship (which is sending in reinforcements and also can engage in battle) deal more damage, survive longer or be in the air longer. I never mentioned how exactly do you get the resources - most of the time you get them when you control a landing zone or control point, and by destroying your opponent's army.
3. The Banner saga trilogy, best described as "Thronebreaker but with more decisions influencing you and your well-being directly". I'd even say that you MUST play it without downloads if you don't like the choice you made. The gameplay is quite simple but it has some degree of tactical depth, and some battles can be quite challenging.