I needed a stand for my Signo Mitsubishi UNI Uni-ball Gel Ink Pen (0.38 mm) set, so I designed one.
The top and base print without supports. The struts have minimal and easy-to-remove supports.
The tolerance for the press-fit struts is a very tight: .1mm. On my printer I had to trim just a bit on one strut stub, but otherwise the fit worked well. To make it easier to insert the stubs into the notches I chamfered their edges using a hobby knife. I added a few drops of CA after assembly just to ensure it stays together but you probably don't even need it.
If I get around to it the next revision might have actual snap-fit struts. We'll see.
I like my pen stands to have very little “slop”; the tight tolerance means you'll need to pull the pen straight up and out of the organizer. If that's not your thing, re-mix it. : )
Pens, of course, aren't included. : ) Looking for the pen set I use? You can use this link to Amazon to buy it. Note that I make a small amount of money if you click the link and buy the pen set.