This is a question I hear a lot about printing of 3D objects. That is why I mention it here as well. I work myself on thingiverse.com
where you can find a lot of good ideas.
And I use Tinkercad
online to make stuff fast. (I use other cad programs as well like Freecad, but online it is always available. And that is handy.)
But even with tinkercad you can find designs and modify them. See for example this Memory Storage Desk
So, I hope my advice did help you. And I hear more tips from other users !