If you're in the mood for something new and GOG isn't your thing with their big sale going on, Humble also have some interesting choices.
There's another 2K publisher sale going on right now, with top deals like Civilization VI (recently got a patch to make Linux online play cross-platform) has 75% off plus the Civilization VI: Rise and Fall expansion is currently 35% off. XCOM 2 is also 75% off and it's easily one of my favourite strategy games. Even better with the War of the Chosen expansion with 50% off. Looking further, you would be pretty mad yourself to pass on Mad Max with 75% off!
The Team17 bundle has a few Linux games, which ends in 23 hours. There's also the current Humble Monthly has Wizard of Legend (excellent in local co-op) along with tons of DRM Free games in the Humble Trove. Additionally, for those of you with a creative side the excellent pixel-art tool Aseprite is also 25% off.
I'm not sure how many will be interested in it but the Hacking for the Holidays book bundle might be interesting to a few of you too.
Finally, there's The Yogscast Jingle Jam 2018 (100% to charity) with a new game unlocking each day. It does have a couple of nice Linux games in it so far!