There are none of them as good as Proton.

For example, AirVPN hasn’t had any security audits and doesn’t seem too interested in them either due to monetary concerns. That’s a deal breaker for me.

Mullvad (or Mullvad on a router with Adguard)

Airvpn, or Azirevpn if you’re ok with few servers

Of those I’ve only used Azire, and it worked well. I’ve seen Airvpn recommended often though