Humble have another bundle! The Humble Day of the Devs Bundle 2019 just recently went live with a small selection of games and some good picks have Linux support too.
In the $1+ tier you get The Haunted Island, a Frog Detective Game and ART SQOOL although neither offer up Linux support sadly.
When you pay more than the average you get Flipping Death and Battle Chef Brigade, the latter of which does actually have Linux support it's just not advertised as such on Steam.
Finally in the top tier both games do have Linux support with Minit (which is fantastic!) and ToeJam & Earl: Back in the Groove. You also get a Day of the Devs VIP Ticket, if you happen to live near San Francisco in the US allowing you to get into the event early and skip any line to get in.
While it's sad it's not a bundle full of Linux games paying $9 for Minit, ToeJam & Earl: Back in the Groove and Battle Chef Brigade is a pretty good deal.
See the full bundle here if you are interested in any of those.