This is a partial list of unnumbered minor planets. Currently, approximately one third of known minor planets remain unnumbered. In this list, only unnumbered asteroids discovered before 1990, and notable unnumbered asteroids are included. The primary reason asteroids remain unnumbered is because they are either lost or discovered recently, and, as such, have not been observed long enough to qualify for being numbered (about a decade). Several new asteroids are discovered every hour, so it would be pointless to attempt to make a list of every one of them.
A · B · C · D · E · F · G · H · J · K · L · M · N · O · P · Q · R · S · T · U · V · W · X · Y
^ in a couple of cases, observations of the asteroids didn't include magnitudes, so it's not known exactly how bright they are. As such, it is impossible to determine absolute magnitude with any level of accuracy.