This will be potentially an ongoing question!

[Sarainia]

I have seen the tiniest black ants in my life wandering around this building in Toronto, Canada, I will one day buy a camera and post a High definition picture of them, but atm will take minimum 4-5 months for the camera, and my laptop camera is 720 for res so prolly not gonna bother trying to do that for how tiny they are, but one day I may just get a 4K camera on a phone! So this will be most likely an ongoing case, unless you know which one, but I would rather get close up picture evidence and see them better through a magnifying glass, they are far too small to be any usual basic black ant in Canada that doesn't bite, so I will keep tabs on them, and may just get on the floor to better look at them at some point but size is to be estimated maybe 1 millimeter width body or less, not including legs, and maybe 2-3 millimeter length, been watching them for months on end and they never get any bigger, it's appearing to be a smaller colony cuz sightings to see and find them is days apart from each other or they could be larger but choose not to come here often who knows! So I'm figuring this is gonna be a long process and is truly the smallest ants I've so far seen in my life so far yet for me that is

[Sarainia]

My best guess atm so far from what I read on them kinda lines up to "Monomorium minimum" but more research I will do and I will try to get pictures of these small guys, I do know for how rare the sightings are it's not gonna be an easy task for me to gather up the evidence, and with my Grainy laptop camera, it's not gonna suffice, so I will try to do 4K, if not I will at best at that point aim for a 1080 for res we will see in time!

[PwnerPie]

I have some, also the smallest I have seen. Less then half the size of a myrmica worker. Turns out they are tetramorium. Queen is bigger than myrmica queen, but still smaller than lasius or formica. But the workers are tiny, too small to sting you, and very adventurous. They are far more outgoing than other ants. The queen also lays tons of eggs, I believe she had ~25 nanitics

[JoeHostile1]

if I were to guess going on only your location and the fact that the ants are “tiny” I would also guess tetramorium because tetramorium like to invade houses and such. But could also be several other species like Lasius which also have tiny workers. There’s actually a lot of different species that are tiny so you should just post a blurry picture and someone may be able to tell what it is.