2FA Apps for Linux Desktop?

keepassxc has 2fa support

Seconding KeePassXC. Has good browser integration too.

Ente Auth

OTP is built in to many password management applications. I use pass and the pass-otp extension.

You can also use OATH Toolkit’s oathtool(1).

Assuming you had the secrets stored in a secrets.json file in your home directory in this format:

{
  "github": "github2FAsecretKey",
  "some_other_account": "2FAsecretKeyForSomeOtherAccount"
}

You could make a simple otp.py script and basic TOTP library to generate them in a script & copy them to clipboard:

#!/usr/bin/env python3

import json
from pyotp import TOTP
import os
from sys import argv

try:
  file = json.load(open(os.path.join('/home','username','secrets.json')))
  if len(argv) > 1:
    totp = TOTP(file[str(argv[1])])
    code = totp.now()
    cmd = 'cb cp $(echo %s | tr -d "\n")' % code
    os.system(cmd)
  else:
    print(f"Available args:\n  {'\n  '.join(list(file.keys()))}")
except Exception as e:
  print(f'Error in OTP: {e}')

Then you just alias otp='f() { $HOME/otp.py $1 };f' in your shell profile/rc and call it with e.g. otp some_other_account or just otp if you forget what key names you gave them to get a reminder list. Obviously you'd want to replace the JSON plaintext file load with an actual secret store if you're not a lazy madman. I am a lazy madman.

Edit: when I stop being lazy I will probably switch to that davel@lemmy.ml suggestion below (pass + pass-otp extension).

Bitwarden

If you use Gnome and Flatpaks there is an app called Authenticator on Flathub

Another idea if you are willing to spend some money is to get a yubikey. Then the tokens are stored on a separate hardware key and it has great android and Linux apps to access codes

Some great recommendations in here already. If you're looking for an OTP only UI: https://gitlab.gnome.org/World/Authenticator

If you use KDE Plasma and want an app which looks like your other Qt apps: https://apps.kde.org/keysmith/

A chrome extension should do the trick

What exactly do you want it to do? You can implement TOTP with a 10 line python script and I probably have a few of those kicking around. I've ended up doing that at least a couple of times.