Why can't I see my THETA/TFUEL tokens in the Ledger/Trezor app?
There is not a native Theta app for Ledger/Trezor yet, so you can't view your Theta tokens on Ledger Live or the Trezor app. However you can access and send them by using your Ledger/Trezor device with the Theta web wallet. If you don't see your address using the Ledger option, try one of the alternative derivation paths from the dropdown menu. Native hardware wallets apps are slated for development in Q1 2021.
Please see here for troubleshooting if you have any issues: https://medium.com/theta-network/theta-web-wallet-adds-support-for-ledger-trezor-hardware-wallets-a11ace6d2799