Dunno if you say this implying that they are not so big or if it's because you really don't know

Fortnite : 400 Millions registered account, 80+ active every month

League of Legends : 180 millions accounts, peak at 32 Millions active daily

Rocket League has 80M average monthly players for more than 2 years now

PUBG Mobile often peaks at 30+ Million player daily

Clash of Clan (mobile game) has maintained its monthly playerbase between 75 and 150 Million players for like 4 years now

Clash Royale (mobile game) has 16M monthly players

The last Dark Souls game (Elden Ring) sold almost 20 Million copies, Dark Souls 3 sold 10 millions,...

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All these games are huge