I've heard great things about Revelate Desings which REI carries. I use a few Apidura bags which have been awesome on my bikepacking trips. REI however, doesn't carry them.
There are so many brands that make bikepacking bags that it is difficult to recommend any specific one. Big international brands and individuals in your home state are making all kinds of awesome gear for adventure riding. The best place to start is https://bikepacking.com/ to get an idea and then check some local bike shops with your bike to see what bags fit your frame. You can also search google for folks that are making bags local to you. Many are willing to make custom bags that would fit your frame perfectly. It will cost more but it feels good to support small artisans.
Revelate, Oveja Negra out of Salida, Co, Ortlieb and salsa. Revelate is an alaskan company and they sponsor Lael Wilcox who might be the best ultra cyclist in the world. On the last tour divide she put french fries and hot dogs with sauce in her top tube feed bag. REI carries Revelate and reddit.com/r/bikepacking seems to like their bags too.
Check out Swift Industries, in Seattle WA. They make bikepacking bags right there in the shop! Really good quality!
The other brands, already mentioned are all great choices too!