Revelation 10:3
and he called out in a loud voice, like a roaring lion. And when he shouted, the seven thunders responded to the voice [of the angel]. [Note: These "seven thunders" have not been previously mentioned].
Revelation 4:5
And lightning flashes and [loud] sounds of rolling thunder came out of God's throne. And there were seven lighted torches burning in front of the throne, which are the seven Spirits of God [i.e., the Holy Spirit. See 1:4].
Revelation 8:5
Then the angel took the incense holder and filled it with hot coals from the Altar and threw it to the earth. [Immediately] there was [heard] rolling thunder, and lightning flashes [were seen] and an earthquake [was felt].
Revelation 14:2
And I heard a sound from heaven like the roar of much rushing water, and like the sound of loud thunder. And the sound I heard was like people playing their harps.
Revelation 15:1
Then I saw another great and marvelous [supernatural] sign in heaven. There were seven angels that had the seven last judgments which would complete the wrath of God.
Revelation 15:7
And one of the four living beings gave to the seven angels seven golden bowls filled with the wrath of God, who lives forever and ever.