Temtem looks to be as close to a Pokémon MMO as legally possible
https://www.pcgamer.com/temtem-is-as-close-to-a-pokemon-mmo-as-legally-possible/
Temtem, an upcoming MMO about collecting and battling monsters also called Temtem, was inspired by Pokémon in the same sense that Starbound was inspired by Terraria: It's a spin on it, but nowhere near a full rotation. Temtem is less 'spiritual successor' and more 'well if you're not going to make a Pokémon MMO, we will.'
The avid folks behind Temtem make up Spanish studio Crema, who you may know from their previous game, Immortal Redneck. Crema recently took Temtem to Kickstarter, seeking $70,000 to help bring it to life. At the time of writing, Temtem's campaign has raised $106,849 and still has 28 days to go. Here's the trailer: