Hi there!
I’ve been using Roots (and now Sage) in projects for some time and I have to say, this is the single greatest discovery I’ve made as a WordPress developer.
I’d like to support the team and help ensure future development, what’s the best way can I contribute? I looked around the site and the GitHub repo for a donate link, but I couldn’t find one!
Thanks,
Gifford
As a start, you can buy a license for Soil https://roots.io/plugins/soil/
There were some cool t-shirts but I think they may have gone now 
Actually I think you can still potentially get shirts, nice thing about Teespring is you just make a reservation with how many you’d like, and once there is enough reservations a countdown will begin again where they’ll start preparing a new run of shirts to go out and people can get in on them if they want:
https://teespring.com/roots-wp
We did do the original run and then a few months ago a second run went out because enough shirts had been reserved 