What are some of the best battle engines you've ever seen games?

"Ho there, wanderer! Stay thy course a moment to indulge an old man. ..."

For a side project of mine I'm creating a game based on Javascript engine I've built almost 5 years ago. I really like the idea of publishing game related content on blockchains to give player's full ownership.

The problem with the majority of these games is that they are mostly revolving around the blockchain side of the story, while the game experience itself is more something additional. If I would end up creating a project I want to create a game that while playing, makes you forget you're "doing it for the crypto". Think about purchasing Hearthstone packs or maybe a board game. You don't get anything of value back from these purchases but you don't mind because you pay for the experience itselves.

Now I wanted to pick your brain on battle engines, and I want you to think outside the box as possible. What is your favorite element of clashing with an opponent player or tackling an npc?

Do you prefer a turn based experience, like Pokemon or Final fantasy?

Or maybe an auto battle experience, where the preparation is key? Like TFT or Splinterlands:

https://splinterlands.com?p=battle&id=c7441a36e83d171218fc408d0c9381a7acb4e5ad&ref=foreveraverage

Or a more fast paced engine where there is little time for choosing, like Zelda:

Shoot me with your ideas, and most important tell me what makes them so fun. Even if it is only one small thing that you truly enjoyed. If you don't really like video games that much I challenge you to think further, board games, card games and so on. There are no bad ideas :)

Edit: Here are some other fun battle engines:

Round based grid system (thanks to @nerdtopiade):

Alternative to a round system, a speed system which dictates when you can make your action: