Sasquatch, also nicknamed "Bigfoot", is the most famous of a diverse family of ape-like humanoids - or is it human-like apes? - that are said to roam the various wild regions of the world, in particular the dense forests and high mountains. Sasquatches are native to North America, but the basic idea is actually found across a fairly wide chunk of the planet, including Russia, China, Tibet... even fucking Australia says it has a giant man-ape wandering out in the bush! They call theirs "the Yowie".
Sasquatches are actually big business; the cult of Sasquatch fans, hunters and believers is actually big enough to qualify as a legitimate religion by some measures. As such, Sasquatches have appeared in a couple of different games over the years.
D&D and Pathfinder
Unlike their Yeti counterpart, Sasquatches have never appeared in Dungeons & Dragons by name - that said, the description of the Alaghi from the Forgotten Realms, which is also known for having yeti, suggests they could be a race of Sasquatches. Although for some reason their art makes them look like sheepsquatches - a lesser-known cryptic that has the body of a sasquatch and the head of a giant sheep.
In Deadlands, Sasquatch are a benevolent race of ape-men who live in the Pacific Northwest, mostly up towards Canada, where they do their best to battle against the wendigo. Sasquatches appeared in the "Marshall's Handbook" for Deadlands Classic (with some info on their culture in "Great Weird North", the Canada splatbook), and then were moved to the "Trail Guide: The Great Northwest" splatbook for Deadlands Reloaded.
Skunk Apes, a southern cousin of the Sasquatch infamous for their foul odor, appeared in the Classic splatbook "River o' Blood".
Monster Hunter International
In Monster Hunter International, Bigfoot and Yeti are wise and reclusive creatures. They have "no bounties because they ain't really a problem." Sasquach are only known to live in the Americas, but no habitat for Yeti is noted. They are really good at not leaving tracks in the wilderness. They have their own language and culture.