This is a compendium of 623,004 type-I QSOs and AGN, largely complete from the literature to 15 June 2019 including SDSS-DR15 and LAMOST QSO DR5. Also included are approx 1.32M high-confidence (80%+ likelihood) quasar candidates from the NBCKDE, NBCKDE-v3, AllWISE, XDQSO & Peters photometric quasar catalogs (citations in Note 7 below) and from all-sky radio/X-ray associated objects which are calculated here. Type-II and Bl Lac objects are also included, plus galaxies with double radio lobes, bringing the total count to 1,986,800. Gaia-DR2 astrometry is used where available, amounting to ~63% of all objects. Changes from version 6.2 are: (1) Quasars added from publications to 15 June 2019, including 4LAC. (2) 3581 galaxies with double radio lobes are added as type=G because the lobes show that they have active nuclei of some kind, even if well hidden. (3) Positional fixes of a few arcsec were done for ~50 legacy objects. (4) Blazar candidates with neither redshift nor radio/X-ray association, about 30 objects, are dropped. Most were stated low confidence in legacy papers. Low-confidence/quality or questionable objects (so deemed by their researchers) are not included in Milliquas. Additional quality cuts can be applied as detailed in Flesch 2015,PASA,32,10. The aim here is to present one unique reliable object per each data row. The catalog format is simple, each object is shown as one line bearing the J2000 coordinates, its original name, object class, red and blue optical magnitudes, PSF class, redshift, the citations for the name and redshift, plus up to four radio/X-ray identifiers where applicable. This catalog can be cited as Milliquas v6.3 2019 update, Flesch E., 2015PASA...32...10F was the published version of this catalog as at 2015. Questions/comments/praise/complaints may be directed to me at eric(at)flesch.org.