Post any coins you deem relevant! Old hands probably know the answer to the question -- let's hold off and see if some of the newer collectors can answer. Julia Domna, AD 193-217. Roman provincial AE diassarion, 10.69 gm, 25.3 mm, 7 h. Thrace, Perinthus, AD 196-211. Obv: ΙΟVΛΙΑ ΑVΓΟVϹΤΑ, bare-headed and draped bust, right. Rev: ΠΕΡΙΝΘΙΩΝ ΝΕΩΚΟΡΩΝ, Homonoia standing facing, head left, holding patera and cornucopia. Refs: Varbanov 219; Moushmov 4530; Schönert-Geiß 540; CN 2877. Notes: Obverse die-match to CN 2877 (BnF) specimen. Constantine II as Caesar, AD 317-337. Roman Æ Centenionalis, 3.86 gm, 18.2 mm. Heraclea, AD 327-329. Obv: CONSTANTINVS IVN NOB C, draped and cuirassed bust, right. Rev: PROVIDENT-IAE-CAESS, campgate with two turrets, no doors; star above. Dot left field; SMHЄ in exergue. Refs: RIC 96; RCV 17241; Cohen 164.
Attached is another bronze coin from Thrace, this one struck in Augusta Traiana, also with a depiction of Homonoia on the reverse with an added altar. Septimius Severus, AD 193-211, AE 27 mm, 15.51 gm, 6 h.
Sounds like the kind of question posed in an IQ test or the kind posed by a professor, otherwise known as a "Guess what I'm thinking" question. Let's see. Both are round. Both seem to be made of a metal, probably a bronze alloy from their appearance. Both have inscriptions, though in different languages. Both are probably very old. Both were issued from within the Roman Empire and an Asian mint. Both have human beings on the obverse sides. Both are pictured in profile. Even though I may not have found the commonality you are looking for I think I should get partial credit for noting all the other common attributes.