World of Sea Battle

VS

FiveM

World of Sea Battle is an indie open-world naval action game with RPG and simulator elements, developed by Thera Interactive. While it features open-world and multiplayer tags, the lack of wide recognition, a major publisher, and mainstream coverage suggests a small but steady niche community. Its indie studio background and limited marketing mean the player base is likely in the low hundreds daily. I do not classify this as a true MMO as there's no clear indication of massive concurrent player interactions.

FiveM, released in 2016, is a popular modification framework for Grand Theft Auto V that enables custom multiplayer servers, especially for roleplay communities. Its active modding scene and the enduring popularity of GTA V have kept its playerbase strong, typically with hundreds of thousands of daily players. However, it's technically not an MMO as individual servers usually host dozens to a few hundred players, not a persistent shared world for thousands.