Anthony Birley translated the first half of the histories for the Penguin edition with a note that it is only there, in the biographies of the emperors from Hadrian to Elagabalus that there is "a reasonable basis of fact, and the student of Roman imperial history can use the earlier Lives with some profit, if due precautions are taken."
Here is a list of the emperors and the authors credited with their biographies:
Hadrian, by Aelius Spartianus
Lucius Aelius, by Aelius Spartianus
Antoninus Pius, by Julius Capitolinus
Marcus Aurelius, by Julius Capitolinus
Lucius Verus, by Julius Capitolinus
Avidius Cassius, by Vulcacius Gallicanus
Commodus Antoninus, by Aelius Lampridius
Pertinax, by Julius Capitolinus
Didius Julianus, by Julius Capitolinus
Septimius Severus, by Aelius Spartianus
Pescennius Niger, by Aelius Spartianus
Clodius Albinus, by Julius Capitolinus
Antoninus Caracallus, by Aelius Spartianus
Antoninus Geta, by Aelius Spartianus
Opilius Macrinus, by Julius Capitolinus
Diadumenus Antoninus, by Aelius Lampridius
Antoninus Heliogabalus, by Aelius Lampridius
Severus Alexander, by Aelius Lampridius
Maximinus Thrax, by Julius Capitolinus
Gordian I, II, III, by Julius Capitolinus
Pupienus and Balbinus, by Julius Capitolinus
