Some Roman praenomina common in the consular fasti clearly died out, e.g. Kaeso and Numerius (an early praenomen of the Iulii).

So...
1.Kaeso
2.Numerius
3.Appius (only used by the Claudii)
4. Servius (most commonly used by the Sulpicii)
5. Tiberius
6. Titus
7. Gaius
8. Marcus
9. Lucius
10. Mamercus (only used by the Aemilii)
11. Spurius
12. Publius
13. Manius
14. Quintus
15. Aulus
16. Sextus
17. Gnaeus
18. Decimus

There are some others that appear early on in the fasti that are uncommon enough not to have official abbreviations, e.g.

Agrippa Furius Fusus (mil. trib. with consular power in 391).
Opiter Verginius Tricostus (cos. 502).
Postumius Cominus Auruncus (cos. 501).
Proculus Verginius Tricostus Rutilus (cos. 486).

However, the common list of praenomina seems to have been used by all noble families (whose members reached the consulship) until Sulla, from whose time onwards we can add a few more random ones (not going into the Julio-Claudians: they're just messed up)...

Faustus Cornelius Sulla (meaning 'fortunate', Sulla's son and his descendants).
Paullus Aemilius Lepidus (suffect consul of 34)
Iullus Antonius (second son of Marcus Antonius, stressing his connection to Caesar, one suspects).
Flavius also seems to have become an imperial praenomen by the fourth century, e.g. Flavius Claudius Julianus (Julian the Apostate).

As far as I know, Maximus was never, ever used as a praenomen. You can't really mess around with praenomina - evidence is pretty clear that random ones were only used by specific families.

Oh, someone wanted to know Nero's praenomen. He was originally Lucius Domitius Ahenobarbus (Enobarbus is the Shakespearian version), but adopted into the Claudians by Claudius.