Gray rat snake - common and beneficial - as the name implies, eats rats, mice, etc. Tucker

You correctly ID'd the one at the top of the photo as an Eastern Garter(Thamnophis sirtalis sirtalis). The dark one at the bottom of the photo is a young Black Rat Snake(Pantherophis obsoletta). Black Rats don't hatch out black; they enter the world as a silvery-gray snake with a bold pattern of black blotches and lines, and gradually turn darker with each skin shed. This snake is still fairly young, as you can still see its blotched pattern visible, like the spots on a black leopard. Where you live, adult Black Rats usually are jet black with white undersides and throats, although in many places throughout their range, they will keep at least some visible dorsal pattern throughout their lives. I'm guessing that with different species coming into the basement, species with very different feeding habits, they are preparing to hibernate there. Both of these snakes are harmless, and will leave come spring. The presence of the Black Rats could be a deterrent for rodents to enter your home during winter.

You should have started a new post rather than adding to the other snake post. The is a Gray Ratsnake (Pantherophis alleghaniensis although sometimes still known as P. obsoletus in older references). You didn't say where you where, but this looks very much like the gray rats we used to get in South Carolina near the Georgia border.

Yah, a couple years back when I was pulling some weeds, I looked down and there was this snake coiled up and hissing at me about two feet from my face. Scared the snot out of me, but it wasn't rattling and didn't strike. I figure it was probably one of these guys. Like I said though, he scared me good. I ran to the garage for a shovel but by the time I got back, he was gone. Although this guy approached me and came within a couple feet of me, he never acted threatening in a any way even when I approached him. He just seemed to be on a mission and kept moving forward.