In the past, I considered buying a subscription to show some support but the silver tier was too much for that and the bronze tier had nothing compelling. To be honest even silver/premium only had "pull mirroring" that seemed relevant to my individual use cases.
Just within the last 7-10 days or so, I added a task to my "to-do" list to upgrade my personal account to GitLab's lowest cost ($48/year) tier.
I don't actually need any of the features from that tier but I absolutely do* get value from my (personal) use of GitLab (mostly centered around / related to my fairly extensive home lab) and wanted to support the company. I'm not aware of any way to make a donation so I decided I'd just pay the $48/year to upgrade my account as an alternative.
I've been working on a (personal, "offline") project for about the last week and a half -- meaning so I've not been sitting at my workstation during that time -- or else I almost certainly would have just upgraded to the now defunct bronze/starter plan.
Maybe I'll just buy some extra CI/CD minutes (which I don't use) or something similar as a way to show support for the company by giving them a few dollars.