Though the Pope of Rome, the Pope of Alexandria, and the Patriarch of Antioch (among others) are the successors of Peter by lineage, all bishops are successors to Peter and this is reflected in a variety of patristic sources. St. Isidore of Seville (+636)
“So Peter first received the power of binding and loosing, and he first led people to faith by the power of his preaching. Still, the other Apostles have been made equal with Peter in a fellowship of dignity and power. They also, having been sent out into all the world, preached the Gospel. Having descended from these apostles, the bishops have succeeded them, and through all the world they have been established in the seats of the apostles” ~De Ecclesiasticus, II.5, M.P.L., Vol. 83, Col. 781-782.
Pope St. Gregory the Great (+604)
“To Eulogius, Bishop. Gregory to Eulogius, Bishop of Alexandria. Your most sweet Holiness has spoken much in your letter to me about the chair of Saint Peter, Prince of the apostles, saying that he himself now sits on it in the persons of his successors. And indeed I acknowledge myself to be unworthy, not only in the dignity of such as preside, but even in the number of such as stand. But I gladly accepted all that has been said, in that he has spoken to me about Peter’s chair who occupies Peter’s chair.” ~Registrum Epistolarum, Book VII, Letter 40
......
The full list compiled by Ubi Petrus and many more resources on ecclesiology in the early church can be found here:
All Bishops Are Successors of Peter (Florilegium) – Ubi Petrus Ibi Ecclesia
Check out his videos here: Ubi Petrus - YouTube