(1) the “mystery of iniquity” (II Thes. 2:7) We cannot comprehend how Satan or Lucifer could exist one moment in heaven as a sinless angel at God’s right hand and in the next moment be transformed into the Devil who sought to raise himself above the throne of God (Is. 14:14).
(2) “the mystery of the kingdom of God.” The parables were spoken openly by Jesus, but only those with the gift of spiritual vision could understand them (Mk. 4:11).
(3) sovereign election of God is also described as a mystery in Rom. 11:25 as applied to God’s temporary rejection of Israel in favor of the gentiles.
(4) “fellowship of the mystery” is a communion of boundless love (Eph. 3:19) that is mirrored in the mystery of the union of husband and wife (Eph. 5:32). Paul took this to be “Christ and the church,” which is also called the “mystery of the seven stars” – “the angels of the seven churches” in Revelation 1:20.
(5) the “mystery of the gospel” (Eph. 6:19; Rom. 11:25), also described as “the mystery of the faith” in I Timothy 3:9). That is the mystery of how God the omnipotent Creator could Himself become a man in order to die in the place of mankind on the cross of Calvary.
(6) mystery of immortality. In The Twinkling Of An Eye "Behold, I tell you a mystery; We shall not all sleep, but we shall all be changed -- in a moment, in the twinkling of an eye, at the last trumpet. For this corruptible must put on incorruption, and this mortal must put on immortality...then shall be brought to pass the saying that is written: Death is swallowed up in victory.
(7) “Mystery, Babylon the Great, the mother of harlots and of the abominations of the earth” (Rev. 17:5).
From here - and also check out other great references
11 Mysteries from this site - http://www.biblicist.org/bible/mystery.shtml
14 Mysteries on this site - http://www.eternalgod.org/lit/booklets/mysteries_view.pdf