The seven thunders spoke, causing what to occur in Revelation?

[vinsight4u8]

Babylon comes in remembrance twice. So, she will get the vials on her for two rounds.

first time
as the seven full vials

second time
as the seven last plagues (vials refilled)

These are the plagues that the end of Rev. warns about,

"...add unto him the plagues that are written in this book."
These are the plagues of the vials full that were written of in the little book that John ate. This eaten book then caused him to have more to prophesy (warn of).

[vinsight4u8]

Rev. 11 ends showing that the next set of plagues will end with great hail. So, it is revealing that the vials full will come soon.

[JudaicChristian]

Revelation 19:6
Then I heard what sounded like a great multitude, like the roar of rushing waters and like loud peals of thunder, shouting: “Halleluyah!

[alishaba]

On the question of the Seven Thunders in Rev 10:3-4, another event in the Bible should be included.

When Paul describes his visit to heaven in II Corinthians 12:1-4, he says that he "heard inexpressible things, things that no one is permitted to tell (NIV)."

When people are taken up into heaven, God does not allow them to tell about everything they hear. What the Seven Thunders spoke may or may not have anything to do with End Times prophecy. We really do not know because God did not allow it to be told about.

[vinsight4u8]

John could not write out the seven thunders words as at the end God will repent of some of the evil that was to come. Just ahead of the 7th trumpet time, part of the evil was called back.
This has been foretold since Deuteronomy, as to God would repent of the evil.

This is what is meant by "finished as he hath declared to the prophets".

in the manner -

It also could not be written, it seems, as John was made to mess up the events that had been revealed -to make "the mystery of God".

When the 14 plagues later come from the seven vials - their part is not included in the mystery of God section.
Why is that?
Because John was told that the mystery of God ends with the start of the 7th angel.
"when he shall begin to sound"