How is There Any Question that Marcion is the Diminutive of Marcus?

'Ηρωδιων (Herodion) — the diminutive of the name Ἡρῴδης (Herod)'
(Nikos Kokkinos, The Herodian dynasty: origins, role in society and eclipse p.313)

Αβλαβιων (1) is the diminutive form of the name Αβλαβιος (1)

Αγαθιων (3) is the diminutive form of the name Αγαθος or Αγαθων (50)

Αγαθοκλιων (1) is the diminutive form of the name Αγαθοκλης (100)

Αγγελιων (2) is the diminutive form of the name Αγγελης (1)

Αγησιων (8) is the diminutive form of the name Αγησις (22)

Αετιων (2) is the diminutive form of the name Αετιος

Αζημιων (1) is the diminutive form of the name Αζημιος (2)

Αθανιων (4) is the diminutive form of the name Αθανις (4)

Αθηναιων (2) is the diminutive form of the name Αθηναιος (44)

Αθηνιων (22) is the diminutive form of the name Αθηνις (4)

Αινησιων (1) is the diminutive form of the name Αινησιος or Αινησων (6)

Αινιων (1) is the diminutive form of the name Αινιος (2)

Αιολιων (1) is the diminutive form of the name Αιολος (1)

Αισιων (1) is the diminutive form of the name Αισιος (1)

Αισχριων (42) is the diminutive form of the name Αισχρος (5) or Αισχρων (43)

Αισχρυβιων (3) is the diminutive form of the name Αισχρυβης (4)

Αισχυλιων (5) is the diminutive form of the name Αισχυλος (85)

Ακταίων (2) is the diminutive form of the name Ακταίος a mythological hunter who fell victim to the wrath of Artemis.

Αλεξιων (18) is the diminutive form of the name Αλεξος (6) or Αλεξων (7)

Αλκιων (1) is the diminutive form of the name Αλκων (2)

Αλυπιων (1) is the diminutive form of the name Αλυπος (8)

Αμεινιων (1) is the diminutive form of the name Αμεινιας (18)

Αμπελιων (1) is the diminutive form of the name Αμπελιος (3) or Αμπελος (2)

Αναξιων (7) is the diminutive form of the name Αναξος (2) or Αναξων (4)

Ανδριων (3) is the diminutive form of the name Ανδρων (33)

Αξιων (1) is the diminutive form of the name Αξιος (3)

Απελλιων (1) is the diminutive form of the name Απελλας (26) or Απελλης (25)

Απιων (2) is the diminutive form of the name Απιος (2)

Αρατιων (9) is the diminutive form of the name Αρατος (15)

Αρισταιων (8) is the diminutive form of the name Αρισταιος (6) or Αριστας (6)

Αριστιων (138) is the diminutive form of the name Αριστις (40) or Αριστος (44)

Αρκαδιων (1) is the diminutive form of the name Αρκαδιος (4)

Αρκεσιων (1) is the diminutive form of the name Αρκεσων (3)

Αρτεμιων (1) is the diminutive form of the name Αρτεμας (23), Αρτεμης (10) or Αρτεμων (57)

Αρτυμιων (1) is the diminutive form of the name Αρτυμων (1)

Αρχιων (4) is the diminutive form of the name Αρχις (2), Αρχος (4) or Αρχων (24)

Ασκλαπιων (1) is the diminutive form of the name Ασκλαπος (12) or Ασκλαπων (8)

Ασκληπιων (2) is the diminutive form of the name Ασκληπιος (1) or Ασκληπις (1)

Ιλαρίων is the diminutive form of the name Ιλαρός (Hilary).

Ηφαιστίων is the diminutive form of the name Ηφαιστος

Ηλεκτρίων is the diminutive form of the name Ηλέκτρα

Ηλιων is the diminutive form of the name Ηλιος

Ηρακλιων is the diminutive form of the name Ηρακλης

Ηραιων (3) is the diminutive form of the name Ηραιος (11)

Ηγησιων (2) is the diminutive form of the name Ηγησιας (22)

Ηγιων (2) is the diminutive form of the name Ηγιας (14)