A while ago I used FreeCAD to design an aquarium stand. Sharing the FreeCAD file, in case it may be useful to someone else.
The final stand photo is attached as well. I changed a few things on the fly, i.e. the width of the table and the height of the middle shelf, and have not updated the CAD model, as anyone using it would probably adapt it anyway.
I did not have a lot of tools, just made it with mainly a saw (got the big pieces cut already at Home Depot), a hammer and a drill. The `workbench' was the packaging box of the subwoofer you see on the left with a cheap OSB board on top. If you notice the top 2x2 bars (supporting the table top) touch each other---that square was the starting point, and got the legs attached. There is a bit of alignment mismatch, it leans a bit towards the front and to the right, which I fixed with small pieces of cardboard (seen in the pic). I and the fishes are all very happy with it
I am hoping to post more complicated projects in the future. This one got me familiar with the basics.
Many thanks to all the good people supporting and developing FreeCAD and a Happy New Year 2020 to all!