PPMXL is a catalog of positions, proper motions, 2MASS- and optical
photometry of 900 million stars and galaxies, aiming to be complete
down to about V=20 full-sky. It is the result of a re-reduction of
USNO-B1 together with 2MASS to the ICRS as represented by PPMX.
A plain positional crossmatch service that allows file and URL uploads
to be crossmatched to DC-internal tables. In general, you want to use
TAP for this kind of thing when it is available, but in a pinch it
might come in handy. Larger catalogues that can be matched against
include GAIA,PPMXL,ATNF Pulsar Catalog, and more.
