I was testing a new topology optimization software, and having issues with a real life part, decided to try the simplest thing I could think of: A shelf mount. This part is optimized for maximum load with minimal material use. The screenshot shows the part under a 50 kg (110 lbs) load (!), with material stress staying under 20 MPa.
In addition, the part is designed to print completely without supports. Print time around 5 hours on my Prusa i3 MK3s.