I do a few.
Bent over rows. This serves to engage the low back muscles unlike the same motion on a machine. I do this for relief of a pinched nerve in my upper back but I won't lift a weight I'm not strong enough to support with my lower.
Low back extension. Bend over and straighten up while keeping everything tight. This really seems to help my 41 year old "old man back"
The other I do is the classic kettle bell swing between the legs and up thing. It's the one you see in any commercial to show how dedicated to fitness someone it. It's mostly a leg workout but I like it because it does move through a whole lot of joints dynamically. I just use a dumbell and hold on tight.
I also do a dumbell bench press just because I think I should. At <140, I am not worried about getting too swole.