Note: This is a "live" catalog of quasars and quasar candidates. The published version is the Half Million Quasars catalog (HMQ: 2015, PASA 32, 10 -- arXiv:1502.06303) which excludes candidates. The HMQ page is here.
MILLIQUAS v4.5 includes NED / SIMBAD sourced quasar data up to 2 May 2015, and includes SDSS-DR12 and SDSS-DR12Q (http://sdss.org/dr12) and the HMQ catalog (see attribution above). 1,153,110 total objects are displayed, including 452,153 confirmed type-I QSOs/AGN from the literature, 611772 photometric QSO candidates from SDSS-based NBCKDE and BOSS, and 54807 radio/X-ray associated QSO candidates. Radio and/or X-ray identifications are shown where applicable, plus, for the photometric and radio/X-ray associated candidates, the probability of each being a true quasar. The threshold for inclusion of candidates is 80% QSO-likelihood.
Quick browse of (flat text) data here , and here is the ReadMe
Get the file (40Mb with references list) here in FITS or as  flat text .
The Atlas of Radio/X-ray Associations (ARXA, 2010 PASA, 27, 283) is here.
Eric Flesch, last updated 10 May 2015