Detexify: handwritten symbol recognition
detexify.kirelabs.org
detexify.kirelabs.org
Similarly, depending on the font, the command to get an upright lowercase alpha is either \upalpha, \alphaup, \otheralpha, or something else. Why?
[ed: Doesn't appear to be a feature of the windows/desktop app :-( ]
Recognizes full equations and even sends it to wolfram alpha to compute result