How to Build a Crystal Out of Electrons

If you bring a whole bunch of electrons together, they are going to be pulling on each other through gravity. But it's not enough to overcome the extreme repulsion they feel towards each other electromagnetic. Can we like stack them together like Lego pieces? Can we get them to form some sort of structure? And then what emergent properties does it have? Does it flow? Is it shiny? Does it conduct electricity? Does it taste good? Zef constant volume or not? These kind of macroscopic properties of electrons stuff.