I forgot about @debian Backports. I wrote about it in an old blog post, and it still exists. It might be a better source that Liquorix for newer kernels to use with Debian Stable, though Liquorix is very Debian-centric. https://backports.debian.org/
I wrote an even earlier post on upgrading @debian Squeeze to Wheezy http://stevenrosenberg.net/blog/linux/debian/2012_0629_upgrade_squeeze_to_wheezy