This is my only solidus, something I say with a twinge of regret given how much prices have increased across the board for this type recently. However, given the historical importance of Heraclius and the massive inflection in the trajectory of byzantine and global history that occurred during his reign, I really can't complain (though I would love to one day add a few more of his predecessors).
The one solidus (and gold coin, period) in my entire collection, I was hoping to get a tremissis I was watching recently but someone beat me to the punch so as of now this is it in regards to gold. In a few months it'll be officially a decade since I bought this coin and prices have gone up quite a bit for solidi since then so I'm glad I got it when I did. It would be nice to get a new one someday but I'm grateful for what I have regardless and the reign of Heraclius does make for a fascinating period of transition between Antiquity and the Middle Ages. This would've been minted towards the very end of his reign as he was setting up his heirs to succeed him. Here's some more info from Forvm Ancient Coins where I bought it from: SH70051. Gold solidus, Wroth BMC 76; Tolstoi 410; DOC II-1 44f (no examples in the collection, refs Wroth); SBCV 770; Hahn MIB 53; Sommer 11.35; Morrisson BnF -, aEF, luster, tight flan, graffiti on obverse and reverse, 8th officina, Constantinople (Istanbul, Turkey) mint, weight 4.336g, maximum diameter 19.3mm, die axis 180o, 639(?) - 641; obverse Heraclius in center taller with mustache, long beard; standing with Heraclius Constantine on right, Heraclonas on left, sons beardless and equal height, all wear crown, chlamys and tablion ornamented with pellets, and hold globus cruciger in right; reverse VICTORIA AVGu H (victory of the Emperor, 8th officina), cross potent on three steps, Heraclian monogram left, E right, CONOB in exergue.