Off the top of my head the ones I like most are from Mexico, Japan, the UK, Russia, and some of the Euro coins. Is there a source where I could just browse the various coins in regular circulation in the world? I started searching on Google, but I got a bunch of results for weird novelty coins from Somalia.
Various countries have coins with holes through them. It may seem mundane to the residents living there, but to those of us with solid coins those look pretty interesting. I've also seen some multi-sided coins rather than the typical round ones.
One neat thing is ancient Chinese coinage has a square hole in a round coin, I always thought that looked cool. Civilization is old in this part of the world, so there are tons of old coins. Song dynasty coins are about 50k VND locally (2.50). Want something older, from the Three Kingdoms period (over two millenia old)? That will be... the same price. They are so common that no one cares.
Ancient Vietnamese coins are a bit harder to find, and look pretty similar too. I have one of the first coins minted in the country, found it in some scrap metal recovered while dredging a river or a shipwreck or something. It's worth... about 50 cents.
Great coins to collect for someone on a budget. Watch out for fakes -- but they are pretty easy to spot.
I've always loved our toonie as well, the two different metals just looks so great. The black ones for remembrance of QEII are especially nice.
I personally have always loved our money in general, a lot of it stands out quite a bit. I do find it quite funny though that even with such unique physical money, we are one of the most cashless countries in the world.
i always thought so too! Dont know if im remembeting right, but as a kid I visited the phillipines and bored waiting for my parents this security guard sshowed us a ccoin with a hole in it. He put the middle of a candy wrapper through it and tied it so it looked like a shuttlecock and the coin weighed it down. And we used it to play hackeysack.
The Ningi is a galactic unit of currency, valued at one eighth of a Triganic Pu. A Ningi is a triangular rubber coin six thousand eight hundred miles along each side. Galactibanks refuse to deal in Ningis, declaring them "fiddling small change." https://hitchhikers.fandom.com/wiki/Ningi
Not really what OP is looking for, but this came to my mind immediately.