If you want a place to play out your own adventures with friends online even when you're not all online at the same time, Hidden Door is worth a look. This social roleplaying platform uses narrative AI to let you play interactive adventures in officially licensed fictional realms like The Wizard of Oz and Pride and Prejudice. It's got player agency so you can do whatever you want within the constraints of each world, and it's designed for multiplayer play. The site also has an Adventure Generator tool so you can create your own adventures, so it's an active, changing experience for you and your friends.
Another good option is Lovelace Studio, a community-sourced multiverse platform that's something of an MMO sandbox. People can build, cultivate and interact with meaningful content alongside other people using AI-powered toolkits. The site is designed to foster community interaction and has a living history of generative quests, so it's designed to be a longer-term experience. You can join realms, form guilds or play alone, so you have agency and a chance to advance.
For something more interactive and immersive, check out Inworld Arcade. This site lets you chat with AI characters by voice or text, with a wide range of characters across different categories. It's good for socializing, interactive storytelling and exploring different stories. Developers can also create and integrate their own AI characters, so it's a good tool for creative storytelling.
Last, Charstar is a virtual character platform where you can create, discover and interact with a broad range of characters, each with its own personality, backstory and abilities. The site uses open-source AI to provide rich and dynamic conversations, so it's a good option for people who like interactive storytelling and role-playing.