There is a thread in the stockpiling forum that outlines what is typically on sale for each month of the year.
But to answer your question, yes, there are certain times of the year that things go on sale and make for really good deals with coupons. For example, all of the BBQ sauces, ketchup, mustard, hot dogs, etc. that are on sale right now are probably at the lowest price they'll hit until next year at this time. Coming up, school supplies will be the cheapest you'll be able to find them all year.
As for the specific items you were asking about...
Campbell's cream soups - I find these saled/clearanced/coupons mostly in the fall/winter time. Last time I seriously stocked up on these was Thanksgiving-ish time.
Stovetop stuffing mix - I'm willing to guess that this is more of a Thanksgiving/Christmas time stock up item. I don't buy stuffing so I couldn't tell you for sure
Frozen Garlic bread - Not sure...but it's really easy to make your own with some homemade french bread, butter, garlic powder and shredded cheese. pop in the oven for 5 minutes and there you have it!
Pillsbury refrigerated crescents - I watch for these on markdown...usually once they're getting close to their best buy date groceries will mark them down. They freeze well, so I stock up when I see them marked down! Otherwise, in my area there aren't very often good sales on these - I know Kroger did have an awesome deal with these a while back...but I don't have a Kroger
Hand Soaps - Not sure. If you watch for the 30c/1 or higher softsoap coupons, Walmart has small bottles for 97c or something like that? So it could be worth picking up a few or stocking up then (I don't know what your target price for handsoap is)
Green Giant Steamers - I'm willing to bet that this is a fall/winter item. That's when I stocked up on them last (and I'm sure when you got your 30 as well). That's my guess just because there are no fresh veggies in season so they are targeting frozen.
HTH - Good luck!