Daniel 7:19
Then I would know the truth of the fourth beast, which was diverse from all the others, exceeding dreadful, whose teeth were of iron, and his nails of brass; which devoured, brake in pieces, and stamped the residue with his feet;
Cross-reference
Daniel 7:7
Parallel
Daniel 7:7 describes the fourth beast that Daniel 7:19 is asking about — identical subject.
Daniel 2:40–43
Parallel
Daniel 2:40-43 describes the same fourth kingdom with iron and clay — parallel imagery.
Daniel 2:33
Parallel
Daniel 2:33's iron legs represent the same kingdom as the fourth beast's iron teeth, linking the visions.
Revelation 13:1
Allusion
Revelation 13:1's beast from the sea with ten horns directly parallels Daniel's fourth beast in imagery.