I'd like to introduce you to Warcana , one of the strangest and most surprising combinations of game genres I've ever seen. It calls itself a "real-time base defense strategy game with a unique deckbuilding mechanic." That's mostly right, but it's only a fraction of the story for so many reasons.
The simple combination of two concepts becomes an entangling weed of game design that wraps around and warps every part of what might otherwise be familiar in Warcana. Because your armies and towers auto-attack, your attention is instead spent on planning your economy, laying out your defenses, and crafting your base. All of that is dictated by the top layer of your strategy: Managing the deck of cards that let you build and summon units.
By doing that Warcana pulls off a trick I'm not sure I've ever seen before: It let me play a deckbuilder to control a base-building RTS. It's weird . I've played a lot of both genres, and I'm still not sure quite what to make of this hybrid mutation.
The basic format of Warcana is head-to-head tower defense where you're responsible both for defending your own stuff and spawning the units that'll take down your enemy. You do this over a series of progressively longer rounds, each with a short safe period at the start where nothing can spawn, then a much longer period where your two islands come together for combat. It happens over and over until only one combatant is left.
At least for the default battle royale and head-to-head modes—there are also.