Fantastic Tower-Defense with Resource Management
I ran into Mindustry by chance a few years ago, and it has come a long way since then. At its core, Mindustry is a Tower Defence with resource management elements like Factorio.
The gameplay is pretty simple: Enemies attack you in waves, and you have to defend your base while maintaining the resources, for example, ammo for your turrets. This is, however, the bare minimum. There's also Attack mode in which the enemy base is also present on the map, and you compete for resources and destroy each other by building units that attack each other. Lastly, an expansive multiplayer with many custom servers brings varied gameplay to the table. There is also a map editor where you can create your maps and thousands of mods since the game is open source.