BlenderKit add-on (for 2.8 too) - free materials, brushes database
I didn't announce here yet our new database, we are really curious about your feedback. If you didn't try it out yet, just give it a shot and try to install the addon ;)
We are doing this with blenderheads for blender, and hope this will be great for everybody.
There's also a slowly commercial part of the whole thing. We do this so we can keep things running, and we believe creators can also make good money when the subscriptions get running. It's quite probable our share of the income will be just enough to cover the server costs.