Space voxel games have been sort of hit-or-miss for me. There’s a fine line between not having enough freedom and having way too much of it.
Avorion strikes that balance really well; the tutorial is good and interactive, and the game plays like a mix of Minecraft and X3, with a procedural galaxy of space empires, pirates and aliens. The building tool is really good; blocks can be scaled down to miniscule bits, allowing you to place sheets of armor and stick frames as well as blocks and prefabricated block patterns. Unsurprisingly the majority of AI ships look Minmatar in design, but you have enough freedom to also create smooth curves.
Plus it’s on sale for $13 on Steam, so naturally I treated myself. So far I can’t put it down.