for bitcoin cash you can use Electron-cash [1] which is an SPV wallet (light wallet) and a fork of Electrum. it is easy to use but make sure to verify the downloaded file and preferably run it on a separate machine than your main which you have your bitcoin wallet. and if you have any bitcoin in the keys, it is best to spend them first before importing them in Electron.

as for bitcoin gold i don't see any wallets released by the team [2]. i have stopped following the development of BTG ever since i dumped my future coins. but it seems to me like they have not yet actually forked. you may need to wait more months.

[1] https://www.electroncash.org/
[2] https://github.com/BTCGPU/BTCGPU/releases