Paul writes about a man called Demas in Colossians 4:14 and Philemon 1:24. We do not know if this Demas was the same person. Thessalonica was a city in the north part of the country that we call Greece.
We do not know who Crescens was. Galatia was the east part of the country that we call Turkey.
Titus was a man who had worked with Paul to teach the Christian message. See Galatians 2:1; 2 Corinthians 2:13; 7:6; Titus 1:4-5. Dalmatia was where the country called Albania is now, north and west from Greece.
Luke had travelled and worked with Paul. He wrote the books in the Bible called Luke and Acts. See Acts 16:10-13; Colossians 4:14; Philemon 1:24.
Paul may have sent Tychicus to Ephesus city to help with Timothy's work there.
Troas was a city on the west coast of the country that we call Turkey.
Priscilla and her husband, Aquila, had met Paul at Corinth city. See Acts 18:1-3. Then they went with Paul to Ephesus and they stayed there for some time. See Acts 18:18-26 and 1 Corinthians 16:19. Later they went to Rome See Romans 16:3-4. They must have been in Ephesus again when Paul wrote this letter.
Paul writes about Onesiphorus in 2 Timothy 1:16.
The Bible includes the name ‘Erastus’ in Acts 19:22 and Romans 16:23. We do not know whether this Erastus was the same person. Corinth was a city in the south part of the country that we call Greece.
See Acts 20:4-5; 21:29, which include the name ‘Trophimus’. We do not know whether this Trophimus was the same person. Miletus was an important city on the coast, south from Ephesus (in the country now called Turkey).