Here Maps and Drive + are still absent from the Windows store, but HERE appears to have fixed whatever blocker disallowed them from offering at least one of their apps on Windows Phone 8.1 devices.
After hearing a few reports that HERE had returned to the Windows Phone store, we can confirm that the HERE app has indeed returned to Windows Phone, but with a caveat. First of all, it is only HERE Transit that is available in the store at the moment. The app is searchable and downloadable on Windows Phone 8.1 devices, but not on devices running Windows 10 Mobile, including Microsoft’s new Lumia 950 and 950 XL. There is no word from Here on when the rest of the apps will return or if they will be updated beyond maintenance updates.
You can download it on Windows Phone 8.1 from the store link below.