The word(s) "eight" appears 31 time(s) in 31 verse(s) in Quran in Mohsin Khan translation.

(21) He created you (all) from a single person (Adam); then made from him his wife [Hawwa' (Eve)]. And He has sent down for you of cattle eight pairs (of the sheep, two, male and female; of the goats, two, male and female; of the oxen, two, male and female; and of the camels, two, male and female). He creates you in the wombs of your mothers: creation after creation in three veils of darkness. Such is Allah your Lord. His is the kingdom. La ilaha illa Huwa (none has the right to be worshipped but He). How then are you turned away?

(22) And (the clouds) that bear heavy weight of water.

(23) And observe the weight with equity and do not make the balance deficient.

(24) Which Allah imposed on them for seven nights and eight days in succession, so that you could see men lying overthrown (destroyed), as if they were hollow trunks of date-palms!

(25) And the angels will be on its sides, and eight angels will, that Day, bear the Throne of your Lord above them.

(26) Verily, We shall send down to you a weighty Word (i.e. obligations, laws).

(27) He raised its height, and has perfected it.

(28) Woe to Al-Mutaffifun (those who give less in measure and weight).

(29) And when they have to give by measure or weight to (other) men, give less than due.

(30) So whosoever does good equal to the weight of an atom (or a small ant) shall see it.