In his opinion, of the thirteen epistles which say that they were written by Paul, critical scholars have reached a near consensus that seven are Paul's: 1 Thessalonians, Galatians, 1 & 2 Corinthians, Philippians, Philemon and Romans.
Agreement that he did not write: 1 & 2 Timothy and Titus is about 90%
Ephesians is about 80%
Colossians is about 60%
2 Thessalonians is a slight majority.

1Th 1:1 Paul and Silvanus and Timothy to the church of the Thessalonians

2Th 1:1 Paul and Silvanus and Timothy to the church of the Thessalonians