Any fans of MMORPGs? World of Warcraft, Final Fantasy XIV, Elder Scrolls Online... There are a bunch of them in development by independent studios and should release in the coming months / years. They don't promise worlds as complex or polished than AAA mainstream MMORPGs, but they feature interesting and often innovative mechanics: multi-crew spaceships, single shard universe (one huge server for all the players), time-limited campaigns, etc. I've made a list out of 18 of the most promising (imo) and popular MMO in development by indie studios. I've posted it a some places already, and if you have a suggestion for this list please let me know!
Dual Universe [Beta]
Setting: Science-Fiction || View: First-Person || Focus: PvP || Budget: ~$25M* || Engine: Unigine 2 || Origin: France/U.S.
Single shard persistent universe shared by all the players
Voxel-based universe: player-made cities, stations and warships
Space warfare: pirate ships, coordinated attacks, skirmishes
Player-controlled global economy: mining, crafting, building, optimization, barter and trade
https://www.youtube.com/watch?v=c6fmPSomoIw&ab_channel=NathanHardy
Camelot Unchained [Beta]
Setting: Medieval Fantasy || View: Third-Person || Focus: RvR || Budget: ~$25M* || Engine: Unchained || Origin: U.S.
Heavily inspired by Dark Age of Camelot
Large-scale RvR battles and sieges featuring more than a thousand players and hundreds of siege weapons
Open world with islands that players can move to strategically reshape the world
Block-by-block construction with server-side stability and destruction
https://www.youtube.com/watch?v=TdK_gUSW9iA&t=2635s&ab_channel=CityStateGames
Crowfall [Beta]
Setting: Medieval Fantasy || View: Third-Person || Focus: PvP/RvR || Budget: $38M || Engine: Unity 5 || Origin: U.S.
Heavily inspired by Shadowbane
Player-created worlds with parcels of land and pre-fab building pieces
Time-limited GvG/RvR campaigns that guilds or factions can win thanks to sieges, skirmishes and capture mechanics
Deep crafting system inspired by Star Wars: Galaxies that is a central part of the player-driven economy
https://www.youtube.com/watch?v=zBtQV5eM5e8&ab_channel=TheBloodyPoint
Pantheon: Rise of the Fallen [Pre-Alpha]
Setting: Medieval Fantasy || View: Third-Person || Focus: PvE || Engine: Unity 5 || Origin: U.S.
Spiritual successor to EverQuest
Deeply social: dungeons require teamwork and group strategy
Combat focuses on preparation and awareness: players will face challenging scenarios that require understanding and skill
Perception system: the world reveals its secrets through the environment
https://www.youtube.com/watch?v=tIqZEMCC5nA&ab_channel=Pantheon%3ARiseoftheFallen
Mortal Online 2 [Beta]
Setting: Medieval Low-Fantasy || View: First-Person || Focus: PvP || Engine: Unreal 4 || Origin: Sweden
Open and realistic sandbox world where player houses can be built almost anywhere
True, real-time combat where outcomes are decided by skill rather than levels or gear
Legendary crafters trading across the globe, famous warriors studying the art of combat, explorers puting names on the map
Individual reputation: people will recognize players by their impact on the world
https://www.youtube.com/watch?v=hTWLlefiy2E&ab_channel=BadmanLasermouse
Ashes of Creation [Alpha]
Setting: Medieval Fantasy || View: Third-Person || Focus: PvP/PvE || Budget: ~$40M* || Engine: Unreal 4 || Origin: U.S.
Nodes system: player participation influences the type of content in the surrounding areas
Open world housing: players have the ability to survey and develop land anywhere in the world
Castle sieges with hundreds of players with many moving parts
Harsh, unforgiving and stunning environment
https://www.youtube.com/watch?v=V_hsJPB8y7k&ab_channel=AshesofCreation
Star Citizen [Alpha]
Setting: Science-Fiction || View: First-Person || Focus: PvP || Budget: $350M || Engine: Lumberyard || Origin: U.S.
Spiritual successor to Freelancer
Procedurally generated and handcrafted stunning worlds
Open world PvP with high speed dog fights with multi-crew ships or intense FPS warfare
Exploration: hidden outpost, abandoned ships and beautiful sunsets
https://www.youtube.com/watch?v=f3atf-YLyCY&ab_channel=RamenStyle
Corepunk [Alpha]
Setting: Cyberpunk || View: Isometric || Focus: PvE/PvP || Unity 5
Seamless open world with fog of war
Players explore the world, participate in trading, complete dungeons, or engage in PvP battles
Day / night cycles as well as weather conditions
Flexible character customization with a wide variety of builds
https://www.youtube.com/watch?v=1_RPcB-9rE8&ab_channel=IGN
Seed [Pre-Alpha]
Setting: Science-Fiction || View: Isometric || Focus: PvP/PvE || Budget: +$36M* || Engine: Unity || Origin: Germany
Players voyage across a persistent, Earth-like planet to harvest resources, collaborate with other players, and conquer new lands
The exoplanet is abundant with all forms of biomes, filled with various habitats, seasons, unpredictable weather, and ecology
As a colony grows, resources, research, and construction will increase, which can permanently impact the economy of the planet
Players can freely construct structures and organize offensive missions to raid other colonies, or join skirmishes
https://www.youtube.com/watch?v=7g8iqoeJS6I&t=20s&ab_channel=Seed
Starbase [Alpha]
Setting: Science-Fiction || View: First-Person || Focus: PvP || Engine: Frozenbyte's || Origin: U.S.
Voxel-based, fully destructible and infinitely expanding universe shared by all the players
In-depth physics simulation make fights (structural durability), exploration and flying spaceships more creative and fun
Focus on building and designing spaceships and stations, exploration, resource gathering, crafting, trading, and combat
Ships are hand made by the players, wired and controlled with a in-game programming language
https://www.youtube.com/watch?v=CF4j_hgKLJ0&ab_channel=ZaffBox
TitanReach [Pre-Alpha]
Setting: Medieval Fantasy || View: Third-Person || Focus: PvP/PvE || Engine: Unity 5
Heavily inspired by RuneScape
Focus on a deep skilling system, massive fantasy open-world, engaging quests, and a complex, skill based combat system
20 skills offering various bonuses and unlockable content
Players play through open-world mini dungeons and bosses, as well as instanced raids
https://www.youtube.com/watch?v=rZgDJaa2eCg&ab_channel=Sorrowh
Ship of Heroes [Beta]
Setting: Superhero || View: Third-Person || Focus: PvE/PvP || Engine: Unreal 4 || Origin: U.S.
Spiritual successor to City of Heroes
Players defend Apotheosis City from criminals and alien invaders and explore whole new planets
Unique character customization with countless options
Thousands of power combinations to form a unique playstyle
https://www.youtube.com/watch?v=-iruwmjzlYw&ab_channel=ShipofHeroes
Gloria Victis [Beta]
Setting: Medieval Low-Fantasy || View: Third-Person || Focus: PvP || Engine: Unity 5 || Origin: Poland
Skill-based combat mechanics à la Mount and Blade
Class-less system with diversified equipment
Open world territory control for guild castles and sieges
Complex crafting system: leatherworking, armorsmithing, engineering, weapon forging, woodworking and more
https://www.youtube.com/watch?v=n5viy3SYIlE&ab_channel=GloriaVictisMMO
Profane [Alpha]
Setting: Medieval Fantasy || View: Third-Person || Focus: PvP || Engine: Unity 5 || Origin: Brazil
Territory conquest: guilds can leave their mark on the game's history by conquering mines and castles
Players can build small towns and great cities in the open world
No class or level: combat style is determined by what players exercise the most
Open PvP and full loot: karma system with restrictions to access cities if the player is a criminal
https://www.youtube.com/watch?v=7uxqavAgBGM&ab_channel=TheGamePiece
Mankind Reborn [Pre-Alpha]
Setting: Cyberpunk || View: First/Third-person || Focus: PvP/PvE || Engine: Unreal 4
Eight player-run factions are locked in endless galactic strife of commerce, intrigue and warfare
Brutal conflicts: combat is entirely skill-based, with full-loot on death rewarding those who master the art of war
Players forge their destiny as an interstellar entrepreneur, a mercenary or a faction leader at the helm of the next chapter
A detailed economic system provides the backbone for mining, production and manufacture fueling conflict and player greed
https://www.youtube.com/watch?v=afuf_Bg-A0o&t=31s&ab_channel=MankindReborn
AdventureQuest 3D [Beta]
Setting: Medieval Fantasy || View: Third-Person || Focus: PvE/PvP || Budget: +$350K || Engine: Unity 5 || Origin: U.S.
Cross platform: can be played on PC and mobile
Ever expanding world: exploration of the lively land with new exciting environments
Randomly generated dungeons that are unique and offer a new experience every time
Random events: dragons could swoop down, the undead may rise, or there could be an Easter egg hunt
https://www.youtube.com/watch?v=BoayorEQl2w&ab_channel=GOLDRAVEN
Foxhole [Beta]
Setting: WW1/WW2 || View: Isometric || Focus: RvR || Engine: Unreal 4 || Origin: Canada
Single shard with hundreds of players: wars that last several weeks and reset after each war
Players are what they carry or drive: player progression is purely horizontal as characters have no stats
Three main roles: soldier, logistics, builder, and many sub-roles: medics, drivers, gunners, artillery, partisan, etc.
Deep logistics and building mechanics: transportation, factories, scrapping, trenches, bridges, defenses (AI), bunker bases
https://www.youtube.com/watch?v=rjZaFamcjfw&ab_channel=ISawABear
Rise Online [Alpha]
Setting: Medieval Fantasy || View: Third-Person || Focus: PvP/PvE || Engine: Unreal 4 || Origin: Turkey
Spiritual successor to Knight Online
Full PvP-based maps and events
PvE content like missions, creatures and bosses that take several groups to defeat
An endless war between two kingdoms
https://www.youtube.com/watch?v=-WABcBlFDQQ&ab_channel=RİSEGAME
Cross post. *Personal estimate, may be inaccurate
Feel free to suggest improvements to this post!