Updated answer, as of Gen 8:
Yes, there are a few ways outside of the Mew Glitch and Events to get Mew.
The Pokeball Plus
A bit pricey, and only one Mew per Pokeball, but you get a legit Mew from there. It's compatible with the Nintendo Switch.
You can get Mew by completing the special research for it, "A Mythical Discovery". From there, you can transfer it to your Nintendo Switch.
There's also another Mew event upcoming in Pokemon Go, I believe for Shiny Mew, but I believe it's timed. Now much is known about it yet.