Augustine, City of God II.27 begins:
vir grauis et philosophaster Tullius aedilis futurus clamat in auribus ciuitatis...
-aster has been added to the stem philosoph-a-- (cf. philosophari, etc.).
Herein is Augustine's verdict on Marcus Tullius Cicero. He has in mind In Verrem 2.5[14.]36 and soon afterwards he refers to In Catilinam III [8.]20.
oleaster tri 'the wild olive' can be cited from Cicero, Sallust, Virgil, and Ovid. Whence oleastellus 'A cultivated variety of olive resembling the wild sort in its fruit' Col(umela) 12.51.3.
OLD's entry for this suffix (p. 191) also cites parasitaster (Terence, Adelpi 779). Cf. parasitari
Also of note is the name of the Pauline commentator Ambrosiaster. Apparently, this name 'Would<->be-Ambrose (perh. 'Ambrose-Wannabe') is not antique, but early modern.->