Here's a simple 5015 Fan Guard Grill with Hex Mesh holes. Nothing too crazy, just to keep people and things from getting sucked in. The design is not too restrictive to the flow. Also check out my 5015 Velocity Stack in my other Thing Uploads
As with all my designs, I have included the Fusion360 file so you can see how I made it or make your own tweaks.
Check out my other designs for other cool stuff for around the garage.........
A quick print. Printed with Zyltech PLA at 210C with glass bed at 60C. Sliced in Cura.