Are backticks used outside of computing?

Is the backtick character ("`") used outside of computing in English? If so, what for?

No, it's not.

The backtick, or the backquote, evolved as a separate character exclusively for computer use. (Wikipedia)

It is actually a grave accent, used in combination with a letter in many languages, but not English, except sometimes to indicate pronunciation.

From wikipedia:

The grave accent, although not commonly applied to any English words, is sometimes used in poetry and song lyrics to indicate that a vowel usually silent is to be pronounced, in order to fit the rhythm or meter

...It can also be used in this capacity to distinguish certain pairs of identically spelled words like the past tense of learn, learned /ˈlɜrnd/, from the adjective learnèd /ˈlɜrn.ɨd/ (for example, "a very learnèd man").

EDIT: As Steven noted in the comments, loanwords which use grave accents often retain them in English.

Accents, sometimes combined with italics, are often applied to foreign terms that are uncommonly used in or have not been fully assimilated into English: for example, vis-à-vis, résumé, pièce de résistance and crème brûlée.