I personally found following two youtube channels, run by established GATE coaching institutions, to be useful.
Students can subscribe to these channels.
Also, go to their playlists and add them to your playlist.
1. GATEMATIC: https://www.youtube.com/channel/UCx87fIpfUYa4N8iddGnxa2g
2. GATE ACADEMY: https://www.youtube.com/channel/UCnaOzPCUym-vNapCjV2p9Pg