The latest thing I 3D printed was a carabiner. I was skeptical on how strong it would be, but it was able to lift a 10 pound weight no problem. I would definitely use this design again if I needed one. Below is how the carabiner looks and a picture of it supporting 10 pounds.

The printing specs were 100% infill, no supports needed. Here is the link to get the code:

https://www.thingiverse.com/thing:489709

You can see more details in the following video: