[neonsunset]

There is https://github.com/linq2db/linq2db which is LINQ to SQL reincarnated.

Of course there's EF Core too.

[WorldMaker]

And NHibernate.Linq and Dapper.Extensions.Linq… Most ORMs in the ecosystem have at least one Linq support library, even if just a third-party extension.

Also, there are fun things that support Linq syntax for non-ORM uses, too, such as System.Reactive.Linq and LanguageExt: https://github.com/louthy/language-ext/wiki/How-to-deal-with...