Short answer: Most of the world, humans, Kossith, and Things.
Slightly longer answer but still kinda short bc i’m tired: Well, knowing that Thedas is in the Southern hemisphere we know there should be a LOT out there unless Bioware has decided in their infinite limitations that there’s only a few islands out there.Now, because we know there was a Qunari colony to the south that became the original Ogers that were wiped out and then the next group that came came from the north-- the same direction as the humans but we don’t know if they came from true north, north east, north west, north by north east, north by north west, which changes the determinations we can draw-- meaning that they either have several groups over several landmasses or their singular landmass could be large enough to have different launching points to grant them access to passable sea lanes through the notoriously treacherous oceans. Something had to have changed, however, either on their end or on the oceans to cut off their return travel to the home continent so they cannot go back and forth-- logistically a Dreadnought type of ship outfitted for long sea travel should be able to cross the ocean if they rationed it out, the Qunari are not ones to lose things easily. So they either lost their maps, the routs changed due to weather, or the lanes are time sensitive upon the motions of the Moons. Given the binary nature of the lunar system, it’s entirely possible that the tides could have been in a lull while the colonies came, probably predicted by astronomy, and when they reached Thedas the people who knew how to study the stars had either died or knew that it wouldn’t come for either decades or centuries more. In that time the knowledge could conceivably be lost in an archive fire, or just to time. Not to say the knowledge of astronomy was lost, just the path back to the homeland. We do know they landed around Par Vallen and have a settlement to the West on the delta [Qundalon, in the Donarks i believe?] but that seems an off-shoot.If we work with that as the assumption for northern passage, and indeed the binary moons heavily dictating safe sea travel past the necessary motions to and from the nearest islands and the seas we know of.Humans we know came from the north-- again with no indication of exact heading-- but we know north. There seems to be some sort of weirdness on the Wiki about Par Vallen but my theory is that the humans managed to land there and then, after encountering either elves or another race, depending on what was there, set sail again to eventually pass through the islands around Seheron and land where Minrathous would be settled. That being said, it’s possible that the humans could have used the same lunar event as the Qunari, or a similar one that calmed a different channel and found themselves over the Boeric sea by mistake. However, because of the sheer number that would have been needed to not have become inbred after the devastation of the blights in later years, as well as the diversity we see in spite of the likely genetic bottleneck that would have been occuring. So either more humans keep showing up from parts unknown and no one really questions it-- and while there is a set of islands to the east, they aren’t spoken of in a way that seems like that happens often. Neither is it really substantial to assume much about the mysterious trade ships that come in from the area to the West that people can’t manage to sail to [Voshai ]. So, we’re left with the presumption that humans had to have come from somewhere else, en masse, in a hurry for some reason or another, with no particular wish to return to wherever they came from and promptly lost how to go back. They settled, they conquered and they consumed. Most likely fleeing some form of famine, drought, disaster, or something equally disastrous.Why do i suspect this?Well, take the Myth of Amaranth:
The land beyond the Amaranthine Ocean is referred in myths as the 'Amaranth'. Amaranth is said to be devoid of any sentient species and all thedosian attempt of colonization have failed. Legends tell that later expeditions found former settlements empty and that the only survivor was driven mad by something and killed himself a short time after being discovered.[8]
Why is this proof? Logistically this should be proof of them wanting to leave Thedas-- BUT what if this is a cultural memory? A left over from the time humanity collected it’s things and went running for the great green place across the sea, where everything was just green forest and nothing else? It’s entirely possible something similar to the Golden City debacle happened, or something entirely different and equally ruinous that sent them running. And so clung this memory to the mind of humanity, then eventually to elven kind as they were caught up and meshed into the mess of things. “Always have a back up, always think you have somewhere to go.”
There’s also the wonder if Bioware has plans for more things out there, and i am pumped to see if there’s more substantial continents or just islands. Or if there’s just islands, why? So on.