Places that have done them or are under construction:

Shanghai (airport to a transfer station outside of downtown): [en.wikipedia.org]
Japan (NEW New Tokaido line): [en.wikipedia.org]

For a deeper dive, see: [en.wikipedia.org]

Most maglevs also use track-mounted linear motors. The concepts are separable, but it works well if there is going to be heavy power to the track anyway for the levitation, and minimizes power needs in the vehicle itself.

TL:DR: the only one that carries passengers at speed today is in Shanghai. The only one being built (and experiencing a number of issues during construction) for longer runs at real speed is in Japan. Several small demonstrator/amusement park/test tracks have been done but all were slow and/or not available to the public. A couple of airport "people mover" setups (relatively slow) were built: the one in Birmingham UK ran for about 10 years but was shut down, and now operates with cable cars; and another was developed in S. Korea and is used at Incheon airport.

In general, they're very expensive, making conventional high speed rail look relatively affordable, but potentially very fast (up to transonic over long distances). While the canonical Hyperloop is conceived more as a pneumatic tube arrangement, it could work (and might work better) as maglev.