Mojca Miklavec
Aditya has just suggested to create a bunch of definitions equal to those in mathdesign. Mathdesign include three typefaces that have not been implemented in ConTeXt yet, and I agree that they could (should) be.
ConTeXt currently has no support for mathpazo (one can always write it), but it uses pxfonts. I don't know if that's better or worse, but at least it works out of the box.
As others have already written: - "Palatino", "Times" (TeX Gyre, actually) - Lucida (if you have the fonts) - Iwona, Kurier, Antykwa Torunska - Euler, Fourier, Concrete Math - never tried it myself
For palatino, times, iwona, kurier (not yet, but should be fixed), antykwa-torunska, see Yue's and Aditya's answer. In Unicode (xetex, luatex) you should use \usetpescript[name] \setupbodyfont[name,sizeorstyleifneeded] and in pdfTeX you need \usetpescript[name][ec] \setupbodyfont[name,sizeorstyleifneeded]
You can take a look at type-tmf.tex, type-one.tex, type-otf.tex and math-*.tex in ConTeXt sources.
Mojca
Thank you so much to all of you who replied. I suppose that the commands of the type \usetypescript[name][ec] \setupbodyfont[name,sizeorstyleifneeded] that you suggested will also load the matching math fonts. I will also take a look at the documents Mojca has referred to. As Aditya and Mojca suggested, it would be great to have the fonts that are supported in Mathdesign...those are beautiful. Thanks again. I will try these definitions out and let you know if I run into any trouble.