Yeah, I have a ton of stuff in my library, and while a lot of it is from bundles (because I actually downloaded and tried the games instead of just ignoring them), a lot of it isn't. Even if you removed all of the bundles from my library, I would still have too many items to manually search.
My "solution" is to download all the games I own locally and put them in different subdirectories. Obviously not an ideal solution - I'm going to miss out on all updates, and systematically downloading and labeling everything takes time - but at least I don't have games disappearing into the black void of my library where I am never going to find them again.