The word(s) "unless" appears 35 time(s) in 35 verse(s) in Quran in Abdullah Yusuf Ali translation.

(21) The Unbelievers are protectors, one of another: unless ye do this, (protect each other), there would be tumult and oppression on earth, and great mischief.

(22) unless ye go forth, He will punish you with a grievous penalty, and put others in your place; but Him ye would not harm in the least. For Allah hath power over all things.

(23) Say: "Of your 'partners' is there any that can give any guidance towards truth?" Say: "It is Allah Who gives guidance towards truth, is then He Who gives guidance to truth more worthy to be followed, or he who finds not guidance (himself) unless he is guided? what then is the matter with you? How judge ye?"

(24) Noah said: "O my Lord! I do seek refuge with Thee, lest I ask Thee for that of which I have no knowledge. And unless thou forgive me and have Mercy on me, I should indeed be lost!"

(25) He said: "O my Lord! the prison is more to my liking than that to which they invite me: unless Thou turn away their snare from me, I should (in my youthful folly) feel inclined towards them and join the ranks of the ignorant."

(26) "Nor do I absolve my own self (of blame): the (human) soul is certainly prone to evil, unless my Lord do bestow His Mercy: but surely my Lord is Oft-forgiving, Most Merciful."

(27) Now when they returned to their father, they said: "O our father! No more measure of grain shall we get (unless we take our brother): So send our brother with us, that we may get our measure; and we will indeed take every care of him."

(28) (Jacob) said: "Never will I send him with you until ye swear a solemn oath to me, in Allah's name, that ye will be sure to bring him back to me unless ye are yourselves hemmed in (and made powerless). And when they had sworn their solemn oath, he said: "Over all that we say, be Allah the witness and guardian!"

(29) For each (such person) there are (angels) in succession, before and behind him: They guard him by command of Allah. Allah does not change a people's lot unless they change what is in their hearts. But when (once) Allah willeth a people's punishment, there can be no turning it back, nor will they find, besides Him, any to protect.

(30) unless they repent thereafter and mend (their conduct); for Allah is Oft-Forgiving, Most Merciful.