Not manyVPN providers offer dedicated Linux apps. However, these providers do offer apps for a range of Linux flavors:
ProtonVPN Linux Client
ProtonVPN — a client is available for many Linux flavors (installation instructions)
Private Internet Access For Linux
Private Internet Access has dedicated clients for four Linux flavors — Ubuntu 16.04+, Mint 18+, Arch, Debian), 10 simultaneous connections, no-logs policy.
AirVPN For Linux
AirVPN offers Linux apps for Debian/Unbuntu, OpenSUSE, Fedora/CentOS, and Arch Linux.
ExpressVPN App For Linux
ExpressVPN has a command-line app for Linux — but no graphical app. However, the command-line app is quite good and it’s available on 64-bit and 32-bit versions of Ubuntu, Debian, Fedora, and CentOS.
Mullvad For Linux
Mullvad is has a Linux client app. I’m not sure what flavors of Linux are supported.
And a few more gui clients.
iVPN.net https://www.ivpn.net/apps-linux/
Perfect-Privacy.com https://www.perfect-privacy.com/en/manuals/linux_vpnmanager_install
PtononVPN https://protonvpn.com/support/official-linux-vpn-debian/
Great stuff. Thanks for sharing.
Here are a few more that have gui apps.
vpn.ac https://vpn.ac/knowledgebase/114/Linux-VPN-client-beta.html
torguard.net https://torguard.net/downloads.php
ovpn.com https://www.ovpn.com/en/guides/ubuntu
KeepSolid VPN Unlimited https://www.vpnunlimitedapp.com/downloads/linux
Hidester VPN https://hidester.com/download-vpn/