Are there legitimate saints not documented in western hagiology? In Croatia the patron saint of Vukovar is Saint Bonus/Sveti Bono. There's nothing in any English Catholic encyclopedia but Croatian wikipedia lists the following facts:


Martyred under Decian (or was it Valens?) in the third century
There's an inscription of his name on a street in Rome.
His body was donated to the people in Vinkovski by Benedict XIV


How common is it for saints of one region to be "left out" in the English hagiographies?
The Roman Martyrology for August 1 says:

Likewise at Rome, upon the Latin Way, [in the third century,] the holy martyrs Bonus the Priest, Faustus, and Maurus, and nine others, of whom it is written in the Acts of holy Pope [St.] Stephen [I].
Romæ, via Latína, sanctórum Mártyrum Boni Presbýteri, Fausti et Mauri, cum áliis novem; qui in Actis sancti Stéphani Papæ describúntur.

cf. also p. 228 of this Roman Martyrology
Pope St. Stephen I reigned from 253-257, during which time Valerian was emperor.