A few links as I'm thinking of it for some of my favorite construction systems / building components. To clarify what I mean, these are systems of generic parts that are compatible with each other and usually used to build something else. Hopefully if that's not clear the examples themselves will clear things up.
- Contraptor - Aluminum parts based on 1” intervals for building whatever you want, like an erector set for grown ups. It's an open source “spec” so you can build your own or buy parts pre-made. Users have built all kinds of both static and dynamic machines with contraptor. Here's the official what is it blurb.
What is Contraptor
Contraptor is a DIY open source construction set for experimental personal fabrication, desktop manufacturing, prototyping and bootstrapping.
- Metal Lumber - perferated metal angle and other profiles Used for shelving etc.