All I have is Mollo's "Uniforms of the American Revolution", which includes images of some Continental regiments' flags. They don't include any Massachusetts regiments, or the 1st Canadian (also known as "Congress' Own", weren't they?) They do include a flag attributed to the 3rd New York, but I'm not sure that it's not from either the 1st or 2nd. I have this image of a flag attributed to the 3rd:
Note the blue field. The flag in Mollo has the same design, but on a dark green field. I suspect that that is actually the 2nd New York's flag, because as far as I can tell from my resources, all three had the same design (which was the forerunner of the design for New York's state flag), with a different field color for each regiment.
As for the 1st Canadian, I only have a text description of a white field, with the initials or monogram, "C O R" (for "Congress' Own Regiment") in script, with "LIBERTY" printed above the monogram, and below it, a red banderole bearing the regimental name "1ST CANADIAN" in yellow. I have no images of that, unfortunately.
I'm sure Larry will have better references than I, since my focus is more on the Seven Years War/French and Indian War. But I hope that helps.
Prost!
Brad