These are a pair of different grommets for the base of the Creator Pro for the hole through which the cables for the HBP pass to the motherboard.
The ones I'd downloaded before needed supports and didn't fit terribly well. These don't need support and clip in firmly.
I am very much an enthusiastic amateur when it comes to designing. My designs tend to have two things in common
1) They serve a purpose. I like to design functional objects which have a real-world use. 3D printing for art is fine, but it's its real-world application which will take the technology forward
2) Wherever possible I design to be easy to print and try to eschew supports or complex printing; modifying the design where necessary and possible to achieve this.