Clash Royale is one of the biggest online multiplayer PvP games right now.
Dead by Daylight Mobile is an asymmetric online multiplayer game. There are four players against a single player.
Dota Underlords is a variant of Dota 2's autochase game mode. Players collect characters, form a team and duel with other players.
Gwent is a mobile version of the card game from the Witcher series. It plays a lot like the version you play in the game.
Hearthstone is the father of the card dual on the mobile phone. It is still very popular despite its age and there are a lot of cards to collect.
Legends of Runterra is a card dueling game from Riot Games, makers of League of Legends. It works like Hearthstone with a few major changes.
Onmyoji Arena is probably the best MOBA currently. MOBA is relatively easy to understand. You and a team compete against an opposing team.
RWBY: Amity Arena and RWBY Deckbuilding Game is a two deck dueling game from the RWBY universe by Rooster Teeth.