Hi all,
I wanted to share what I've built so far in "dark side" gold (a term coined on another forum as anything non-USA). To say my collection has changed a lot over the last few years would be a major understatement. My username is due to my love of early US gold, but after accomplishing most of my goals there, I wanted to go earlier and immediately started down my journey to the dark side. I still have my main US collection, but except for a few specific pieces I'm looking for, I don't expect to grow it moving forward.
My darkside journey started with a 1794 8 escudo but that wasn't enough... I then started moving back through the centuries to a 1602 Sword and Sceptre, then an English noble, then some late Byzantine coins, and then a solidus of Valentinian. I was still undecided on my collecting direction, focusing still on
US coins as they felt "safer". Then at an
ANA show, I saw an Alexander the Great Stater and was hooked on ancient gold, with a grip that was not going to let up.
Since then, I've been narrowing my focus, looking for pieces that have an inherent rarity, are visually diverse, and are of a high grade without problems. I've been getting everything slabbed by NGC - I know they aren't as popular in the non-US markets yet but they provide a fantastic service for validating the authenticity and assessing any damage. In particular with ancient gold, edge issues are very hard/impossible to infer from pictures and NGC gives me a great deal of additional confidence. So far every coin I've sent in has graded problem free and I'm crossing my fingers that this continues with my latest shipment to the slab factory!
Long term, my goal is to complete a set of The Twelve Caesars and the "Five Good Emperors" in gold. This is ambitious and will take a considerable amount of time to complete, but the enjoyment I've gotten out of the quest so far has been well worth it.
Without further delay, here are the images. I hope you enjoy them as much as I do!
Antoninus Pius (Calico 1650). Ex. Biaggi, the Calico plate coin, in Mint State. The reverse type is interpreted as showing Pius as the refounder of Rome and of Roman morality, following in the footsteps of Augustus who had also wanted the name Romulus. I have a disproportionate number of Antoninus Pius aurei in my collection because I seem drawn to him as an emperor. He is definitely atypical as Roman emperors go, but I like that about him. He made some major improvements to this world, in particular creating the concept of "innocent until proven guilty" and many humanitarian efforts.

Another Antoninus Pius, now in an NGC Ch AU 5/5 - 4/5 Fine Style holder, Calico 1590.

Yet another Antoninus Pius, not yet holdered.

Hadrian (Calico 1226), also a Calico plate coin for the type, not yet holdered

Domitian, in an NGC Ch VF* 5/5 4/5 holder. The luster on the obverse is impressive, and it's largely due to the way this coin was incorrectly produced. The obverse die is normally the bottom die, creating a convexity to the flan. However, this coin's obverse is concave, made by the obverse die being on the top, showing that this particular pairing had both dies interchanged.

Nero, from Lugdunum, in an NGC AU holder. The reverse is of Roma standing right, placing left foot on a pile of enemy arms before her, and inscribing the shield which she balances on her left knee. This reverse type and the contemporary "Virtus" type which was introduced alongside it in 61AD, might actually depict a pair of statues of Roma Victrix erected by the Senate (EX S C) in commemoration of two victories of Nero's armies in Britain and Armenia.

Nero, from the Boscoreale horde in an NGC XF holder. While considerably less expensive than the previous coin and with a flan flaw on the reverse, I prefer this one due to the wonderful toning and it being from the Boscoreale horde.

Arsinoe II Octadrachm, in an NGC Ch XF 5/5 - 5/5 holder. If you ever have an opportunity to feel one of these in hand, I highly recommend it. They are stunning coins - almost a full ounce of gold from 200BC.

Ptolemy IV Octadrachm, not yet holdered, but one of the best I've seen. These usually have a large amount of die rust but this example is of a early state as it has very clear surfaces.

Alexander the Great Stater, NGC Ch AU 5/5 - 5/5

1725 Brazil 20000 Reis, in an NGC AU55 holder. This is a massive coin (almost two ounces of gold) - I believe the largest gold coin minted for circulation up until that point.

And to round out my dark side gold, my Scotland Sword and Sceptre which I cracked out of an NGC VF35 to get a better picture. I had the opportunity to acquire an NGC AU55 but I dramatically preferred this one for its look.

While I'm here, here's a few pieces from my US collection as well. Worst case, it will hopefully show some US collectors that it's okay to like both liteside and darkside material :)
1808/7 $5 PCGS AU58, BD-1, the R6 variety

1799 $5 NGC AU53, the R6+ variety. I bought this because of the die cracks on the reverse - I've never seen a gold coin with this extensive of die cracks.

Bar cent, NGC AU58, ex Mike Ringo. I looked for a nice bar cent for very long time and missed this one at auction, but found the dealer who bought it and made him a nice offer so here it is!

Pine tree shilling, PCGS VF35 CAC, an R5+ variety with backwards 'N's. I love overdates/misspellings and this one certainly fits well with my others (that I don't have pictures of at the moment, unfortunately)

1851 $50 Humbert Slug, in a PCGS XF details holder. I didn't mind the details designation as I cracked it out as soon as I received it. This is an incredible coin and truly fun to see.

1907 HR Saint, PCGS AU58 CAC.

And finally, here's the yellow metal in its natural, non-coin form. This is from the Eagle's Nest mine in California, measuring about three inches tall by two inches wide (and about 2cm deep). I spent a long time looking for the "right" crystalline gold and this had everything I was looking for:
Thanks for looking!