Oes

A, aes; Bee, Bees; Cee, Cees; Dee, Dees; E, Ees; Eff, Effs; Gee, Gees; Aitch, Aitches; I, Ies; Jay, Jays; [...] En, Ens; O, Oes; Pee, Pees; Kue, Kues; Ar, Ars; […] Wy, Wies; Zed, Zeds.

Source: wiktionary

Mouthing out his hollow oes and aes, / Deep-chested music.

Source: wiktionary

These names […] may form regular plurals; thus, Aes, Bees, Cees, Dees, Ees, Effs, Gees, Aitches, Ies, Jays, Kays, Ells, Ems, Ens, Oes, Pees, Kues, Ars, Esses, Tees, Ues, Vees, Double-ues, Exes, Wies, Zees.

Source: wiktionary

[It] is desirable [...] that we may have a shorter and simpler term in stead of Double-u. [...] Dr. Webster [...] is not yet tired of his experiment with "oo;" but thinks still to make the vowel sound of this letter its name. Yet [...] If W is to be named as a vowel, it ought to name itself, as other vowels do, and not to take two Oes for its written name. Who that knows what it is, to name a letter, can think of naming w by double o?

Source: wiktionary