I created these to mount my RGB LED strips to my computer and desk. The problem I had was the little square 3M taped brackets worked well, except that for longer strips the unsupported segments of the strip might be curved or bent. To avoid that, I created longer brackets. I purchases some 3M double-sided foam tape from Amazon to mount the brackets to the surface I wanted the lights on.

I made these to be ~100mm long by default, but using Cura, I was able to shrink/extend the brackets pretty easily (disable the setting that scales all parts uniformly, so you are only modifying the length).

The "Flush" version is for use cases where you want the light to sit on a surface flatly, like on the top of a shelf, but facing forward from the shelf to be seen from next to the shelf. The "Protruding" version is for use cases where you might have the light mounted to a wall directly, and want the light facing perpendicular to that surface. Really, just look at the bracket and imagine putting a strip in there, and you can probably figure out which you should be using.

Finally, it might be useful for other sized strips, but might require some scaling adjustments.

I have used this with the following strips (Not affiliated with either, just for reference):

novonest Digital RGB Strip,2x15.7inch(400mm)5V 3-pin Addressable RGB LED Strip Kit For PC,Come with Sata Power Cable and Remote,Compatible with Aura SYNC,Gigabyte RGB Fusion,MSI Mystic Light Sync,RF40

and

Phanteks NEON Digital-RGB LED Strip M1 (PH-NELEDKT_M1) – 1x 1-Meter Smooth Lighting Strip, Full-Color Range, Flexible mounting

For the "flush" version of the bracket, I printed it by rotating it to print vertically so that supports wouldn't be needed. In this case, I strongly recommend a brim and to slow down printing a hair to reduce jerking and potentially knocking the print tower over.