2. Besides the forms in 338, Hom. has gen. ὅο (miswritten ὅου) and ἕης.
3. Hdt. has ὅς, ἥ, τό, οἵ, αἵ, τά. In the oblique cases he uses τοῦ, τῆς, etc.; though, especially after prepositions capable of elision, he has the relative forms, as δι' οὗ, παρ' ᾧ, κατ' ἥν, ὑπ' ὧν; also ἐς ὅ.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].