For my interests, mostly 9 mm has it for me these days, although this nearly short enough wavelength to be UV diode has a 5.6 mm diameter and produces a lot of power, but at 1.5 watts shifts more towards blue to 410-412 nm:
These laser diodes are extracted from laser phosphor video display units. The laser diode is in a standard 5.6mm can. The diode leads are isolated from the case and the polarity is shown in one of the pictures.
Welcome back, John. I do think I remember you. It depends on what you want to build as far as which diodes may interest you. I am more interested in wavelengths than output power, so I have been involved in testing many of the new Sharp diodes. I have a few from 477nm to 502nm.