Games like Celtic Heroes

AdventureQuest 3D is a free-to-play cross-platform MMORPG that allows you to explore an ever-expanding world with thousands of other players. Choose from various classes, battle monsters, complete quests, and participate in seasonal events. The game offers real-time combat, player vs. player modes, and the ability to customize and decorate your own home.

"Aura Kingdom is a historically-inspired, anime-styled MMORPG with a massive open world and diverse customization options. Players can choose from ten classes, each with unique skills, and are joined by powerful Eidolons. Questing and combat against monsters with varying skills make up the majority of the game, with the option to play solo or in a party."

A mobile MMO for Android and iOS

"Riders of Icarus" is a free-to-play MMORPG that allows players to capture and train mounts for combat and exploration in a vast fantasy world. The game features both PvE and PvP modes, with a heavy emphasis on aerial combat and epic boss battles. Players can choose from various classes, each with unique abilities and playstyles, as they uncover the mysteries of the world of Icarus.

EverQuest II is a free-to-play MMORPG with deep gameplay and a thriving community, now spanning 18 years and 19 expansions. Featuring 125 levels, countless quests, diverse environments, and extensive character development options, it offers a rich fantasy world to explore with support for various play styles including solo, group, raid, and PVP. Enjoy an independently leveled tradeskill system, robust housing, and a myriad of creatures to battle.

"Wakfu is a massively multiplayer, turn-based strategy game set in the World of Twelve. Engage in action-packed, tactical battles with 18 unique classes, and choose your path as a warrior, politician, merchant, or craftsman. With a humor-filled universe and a player-driven economy, Wakfu offers a limitless and dynamic adventure."

Eterspire is a fantasy MMORPG featuring cooperative multiplayer battles and a richly crafted world. Players level up through skillful grinding, challenging PvE trials, and strategic teamwork, all accompanied by stunning graphics and a phenomenal soundtrack. With an interesting plot and plenty of humor, it offers a rewarding classic MMO experience.

Tree of Savior is a Korean MMORPG game.

ArcheAge: Unchained is a sandpark MMORPG that offers a fresh start in a vast, open world with new economical and political systems. Players can engage in various activities such as farming, trade, and PvP combat while exploring continents and sailing the seas. This version of the game is a buy-to-play model, differing from the original ArcheAge's free-to-play model with optional patron subscriptions.

"Vindictus is a historical hack and slash massively multiplayer online game, where up to 2 players can play together in co-op mode or single-player. The game features brutal combat with complex and fast-paced system, allowing players to utilize combos, magic and environment to defeat enemies. Choose from 16 distinct characters, each with unique skills, armor and personality."