MiniKey is the simplest one time password generator for two-factor authentication. MiniKey lives in your menu bar, and lets you copy generated codes with a click, and drag codes from MiniKey into authenticating apps.
Auth. is a 2FA and OTP management tool for everyone. Works with all Apple personal devices using iCloud Keychain. Scan the QR Code and Done! Or you may add your account manually from your provider. Safari extension is also available for auto-fill-in.