flat spring that works well —

Founded flat spring that works well models & stl files for printing
The Stinker flat bottom
carvellwakeman
Sprung Keyring clip
Mini_Spoon
Bag Clip  Spring Loaded
NWP_Engineering
Foldable Cube  Print Flat
DesignMakeTeach
Di3 hotbed spring cup
Coder-Tronics