EDIT: The original controller was WAY more popular than I expected, so, with some comments about the design that were DM'd to me, I have edited the design to be more compatible, the new design no longer has clearance issues with the PS4 analogue sticks, the only downside being that it is no longer compatible with the GameCube Controller, if you wish to use a mount for the Gamecube controller, I would suggest using the original design, as that will still work, this was simply due to the unorthadox shape of the GC controller making the design a lot harder to make universal, I thought that having the design work for PS4 controllers would be better since that is more used.

So I was looking for a mount for all my different controllers, but most are designed for stands or just a single controller, and while I designed this specifically for the joycon grip, I found that it works with most controllers, its not perfect, the gamecube controller actually has to be put the opposite way round and the arms are SLIGHTLY too narrow for the ps4 controller, but as you can see in the photo, they do stay on there just fine. The screw holes were just designed from the screws I had on hand but they are 3.4mm wide so if you can find something about that size it should work.