I recently uploaded several sets of procedural materials to BlenderKit. Get them in Blender 2.8 in the addon(it’s directly in blender). If you upload yours, share them here too ;). The license allows to remix any procedurals also for redistribution on the site. (www.blenderkit.com)
1st set:
Woods and tiled woods (the boards are mostly procedural wood tiled with procedural ‘Tiler’):