The Swedes
The Swedes are mentioned in a few brief passages. In one passage, they are said to be ruled by King Ongentheow, who is killed in battle by the Geats, the people of Beowulf. In another passage, the Swedes are said to have invaded the Geatish kingdom, but they are defeated by Beowulf.
The Frisians
The Frisians are also mentioned in only a few brief passages. In one passage, they are said to be ruled by King Finn, who is killed in battle by the Danes, the people of Hrothgar, the king of the Danes. In another passage, the Frisians are said to have invaded the Danish kingdom, but they are defeated by Beowulf.
The Swedes and the Frisians are both peripheral to the main story of Beowulf, but they serve to provide some historical context for the poem. They also show that the world of Beowulf is complex and multifaceted, with many different peoples and cultures interacting with each other.