https://phys.org/news/2018-11-astronomers-luminous-high-redshift-quasar.html

However, high-redshift QSOs are extremely rare and difficult to find. So far, only two quasars with redshifts over 7.0 have been identified. This limits our understanding of SMBH growth mechanism and reionization history.

Now, a group of researchers led by Feige Wang of the University of California, Santa Barbara (UCSB) announced the finding of a new quasar with a redshift above 7.0. The new discovery is part of the team's ongoing search for distant quasars and was made using photometric data from the DESI Legacy Imaging Survey (DELS), Pan-STARRS1 (PS1) imaging survey, as well as Wide-field Infrared Survey Explorer (WISE) mid-infrared all-sky survey.