"CNC Kitchen" published this great video on how he designed gardening clips for his raspberries. He focuses on how to design thin-walled object in Fusion 360 and how to make it more weather resistant and stronger by annealing them in his oven.
Here is the video where you will learn a nice and easy design flow process and see several tools in action:
Here is the clip STL:
Here is the CNC Kitchen YT channel:
And here are the PLA clips in the oven at 80C for 1 hour: