Commandos to me is the start of a different lineage of real-time tactical stealth games, which goes on to include Desperados, Shadow Tactics, and Shadow Gambit (yes, most of those were made by the same team).

Outside of the OGRE-alikes (FO Tactics, FF Tactics, Disgea, and so on) some other options for tactical games that are a little different:

• Nexus: The Jupiter Incident - sort of a 4X game mixed with tactics, or like Homeworld with a lot fewer units
• Myth: The Fallen Lords (and sequels) - classic pre-Halo Bungie titles that mix RPG and strategy. Somewhat defining for the RTS genre too.
• UFO: Aftershock and sequels - a series that tried to revive XCom before Firaxis rebooted it. Not as good, but pretty interesting and fun, a little easier than old school xcom but not as polished as the newer ones.
• Cannon Fodder - a UK classic, very arcadey but very fun and lighter than all these other “serious” games