any: [OE] Any is descended from a prehistoric Germanic compound meaning literally ‘one-y’ (a formation duplicated in unique, whose Latin source ūnicus was compounded of ūnus ‘one’ and the adjective suffix -icus). Germanic *ainigaz was formed from *ain- (source of English one) and the stem *-ig-, from which the English adjective suffix -y is ultimately derived. In Old English this had become ǣnig, which diversified in Middle English to any and eny; modern English any preserves the spelling of the former and the pronunciation of the latter. => one
Old English ænig "any, anyone," literally "one-y," from Proto-Germanic *ainagas (cognates: Old Saxon enig, Old Norse einigr, Old Frisian enich, Dutch enig, German einig), from PIE *oi-no- "one, unique" (see one). The -y may have diminutive force here.
Emphatic form any old ______ (British variant: any bloody ______) is recorded from 1896. At any rate is recorded from 1847. Among the large family of compounds beginning with any-, anykyn "any kind" (c. 1300) did not survive, and Anywhen (1831) is rarely used, but OED calls it "common in Southern [British] dialects."