Does Google provide Material Design building blocks for designers (i.e. ready to use components as psd files)? I haven’t found any in the specs.
Google doesn’t provide ready made PSDs, no, but they provide better things.
Check out Google’s Material Design Specifications which is packed with all sorts of guidelines of how to design in a material way, from the style and layout to usability and animations.
If you’re looking for help on the coding/implementation side, you can check out Material Design Lite, a starter pack of sorts. Check out the blog post for more information. Google has also released some ready-made templates using MDL which can be found here.
For general information regarding Google’s Material Design, check out their page for it.