PCB part naming for LEDs
We had lots of discussions about component prefixes, but the main idea was to use as much single letter prefixes. So diodes are "D", whether they're LEDs or rectifiers. On a schematic the symbol should make the difference clear, on a PCB the silk outline may, though maybe not always for SMDs. Once the board is populated it should be clear in any case.

Sometimes components are so close together that there's simply no room for refdes's. In that case we only have the outline on the silk, and in the documentation have an enlarged layout where the refdes appears inside the outline. This means that you need two silk layers per side, one for the outline, one for the refdes, so that you can selectively disabled the latter, or even both is possible.