Another hit multiplayer game from Supercell, the makers behind Clash of Clans and Brawl Stars is Clash Royale.
Clash Royale is similar to Clash of Clans, only it's way different and played from the top-down.
It's extremely fun, addicting, casual, exciting, yet frustrating all at the same time. Clash Royale is a real-time strategy and card collecting game. You will battle against others in real-time and try to outplay or outsmart the opponent. Take down a few towers and win the battle.
Then earn chests to unlock more cards, collect them all, and upgrade troops. While we wouldn't necessarily call this a "casual" game, as it's extremely competitive, I play it casually while sitting around the couch watching TV. Whether that's doing Clan Games, Clan Wars with my friends, or just 2v2 battles with whoever is online. Just don't let the game get you too upset.