I designed this for my console controller collection and it's meant to be as easy to print and modular as possible so I can continue building onto the same stand. It was designed to fit the contours of an Xbox (One, Series X, Series S) controller but works just fine for Playstation (PS4, PS5) controllers as well.
A totally modular tree/rack can be constructed from just three unique pieces. You'll need to print a Controller Main piece for each controller you have, a Controller Tree Connector for each layer of the tree (these can be set up as 2 or 4 controllers each). Finally, a stand can be constructed from a connector piece and either 2 or 4 Controller Tree Leg pieces which simply snap onto the connector piece.
I've tested this up to 5 layers (up to 20 controllers) but it feels plenty sturdy to keep going even beyond that.