I usually design only part of a product. A schematics diagram, a PCB, a firmware, a test program, or a test kit.
But sometimes I design a product alone from start to finish, or took significant part of its creation.
Small projects to show my style and skills.
Unfortunately I usually work under an NDA, which is sometimes so strict, that it does not allow me to mention even the name of the project.
Therefore I cannot show anything serious here.