Its interesting you say you have studied the ECF in depth so you would know these writings then? Id say this is a good smattering of the men who shaped the Church.
Clement of Rome
Accept our counsel and you will have nothing to regret. . . . If anyone disobeys the things which have been said by him [Jesus] through us, let them know that they will involve themselves in no small danger. We, however, shall be innocent of this sin and will pray with entreaty and supplication that the Creator of all may keep unharmed the number of his elect (Letter to the Corinthians 58:2, 59:1[A.D. 95]).
Ignatius of Antioch
You [the See of Rome] have envied no one, but others have you taught. I desire only that what you have enjoined in your instructions may remain in force (Epistle to the Romans 3:1 [A.D. 110]).
Irenaeus
But since it would be too long to enumerate in such a volume as this the succession of all the churches, we shall confound all those who, in whatever manner, whether through self-satisfaction or vainglory, or through blindness and wicked opinion, assemble other than where it is proper, by pointing out here the successions of the bishops of the greatest and most ancient church known to all, founded and organized at Rome by the two most glorious apostles. Peter and Paul, that church which has the tradition and the faith which comes down to us after having been announced to men by the apostles. With that church, because of its superior origin, all the churches must agree, that is, all the faithful in the whole world, and it is in her that the faithful everywhere have maintained the apostolic tradition (Against Heresies 3:3:2 [inter A.D. 180-190])
Clement of Alexandria
“[T]he blessed Peter, the chosen, the preeminent, the first among the disciples, for whom alone with himself the Savior paid the tribute [Matt. 17:27], quickly g.asped and understood their meaning. And what does he say? ‘Behold, we have left all and have followed you’ [Matt. 19:27; Mark 10:28]” (Who Is the Rich Man That Is Saved? 21:3–5 [A.D. 200]).
Tertullian
“For though you think that heaven is still shut up, remember that the Lord left the keys of it to Peter here, and through him to the Church, which keys everyone will carry with him if he has been questioned and made a confession [of faith]” (Antidote Against the Scorpion 10 [A.D. 211]).
“[T]he Lord said to Peter, ‘On this rock I will build my Church, I have given you the keys of the kingdom of heaven [and] whatever you shall have bound or loosed on earth will be bound or loosed in heaven’ [Matt. 16:18–19]. . . . Upon you, he says, I will build my Church; and I will give to you the keys, not to the Church” (Modesty 21:9–10 [A.D. 220]).
The Letter of Clement to James
“Be it known to you, my lord, that Simon [Peter], who, for the sake of the true faith, and the most sure foundation of his doctrine, was set apart to be the foundation of the Church, and for this end was by Jesus himself, with his truthful mouth, named Peter, the first fruits of our Lord, the first of the apostles; to whom first the Father revealed the Son; whom the Christ, with good reason, blessed; the called, and elect” (Letter of Clement to James 2 [A.D. 221]).
Origen
“*f we were to attend carefully to the Gospels, we should also find, in relation to those things which seem to be common to Peter . . . a great difference and a preeminence in the things [Jesus] said to Peter, compared with the second class [of apostles]. For it is no small difference that Peter received the keys not of one heaven but of more, and in order that whatsoever things he binds on earth may be bound not in one heaven but in them all, as compared with the many who bind on earth and loose on earth, so that these things are bound and loosed not in [all] the heavens, as in the case of Peter, but in one only; for they do not reach so high a stage with power as Peter to bind and loose in all the heavens” (Commentary on Matthew 13:31 [A.D. 248]).
Cyprian of Carthage
"The Lord says to Peter: ‘I say to you,’ he says, ‘that you are Peter, and upon this rock I will build my Church.’ . . . On him [Peter] he builds the Church, and to him he gives the command to feed the sheep [John 21:17], and although he assigns a like power to all the apostles, yet he founded a single chair [cathedra], and he established by his own authority a source and an intrinsic reason for that unity. Indeed, the others were that also which Peter was , but a primacy is given to Peter, whereby it is made clear that there is but one Church and one chair. So too, all [the apostles] are shepherds, and the flock is shown to be one, fed by all the apostles in single-minded accord. If someone does not hold fast to this unity of Peter, can he imagine that he still holds the faith? If he [should] desert the chair of Peter upon whom the Church was built, can he still be confident that he is in the Church?" (The Unity of the Catholic Church 4; 1st edition [A.D. 251]).*