Legends of Runeterra

Legends of Runeterra is a card dueling game similar to Hearthstone (another excellent free-to-play game). Players collect cards, build decks, and duel each other until someone wins. You pick a champion and build the deck around it, which helps define your strategy. It’s honestly a lot like the Commander game type in Magic: The Gathering.

Apart from this game and the one above, Riot Games also makes Teamfight Tactics, another good free-to-play game. Of course, there are other excellent card-style dueling games here as well.