T-Mobiles 'unlimited' isn't.
It's near enough. Their highest tier 4G/LTE (yes, annoyingly called unlimited) allows for 21GB of high speed data before dropping down to 128KB/s. Same with AT&T's grandfathered plan. Don't know about Sprint, but I doubt its any higher.
You also get data stash - I have 20GB in my stash and build it every month. Occasionally I dip into it (like when I do a lot of driving around for trips or business).
With TMO, you get 7GB/mo of tethering with that plan - and the data stash can leverage that so you can in one month tether 10's of GB if you need it.
Also music streaming is zero-rated on TMO with most streaming services (Apple music, Google, Amazon, Spotify, Pandora, etc) covered. So you're not going to have to spend GB's on that either.
Maybe you can get unlimited with VZ, but do they allow for tethering as well? Do they zero-rate music streaming?
T-mobile is as good as you can get right now without going for the "unicorn" of truly unlimited.