Adding to the chorus....
Here's how I see the hierarchy of titles from Fiction House and as Donut has previously stated, there are obvious exceptions and classic covers in all the runs that are difficult to find in grade, or at all, and sell for multiples of guide. There are so many books that should be broken out in the Overstreet, but have yet to be singled out. If I had my Gerber with me, I'd list the top covers that aren't broken out....but I'll leave that to all your imaginations.
Planet
Jumbo
Rangers
Jungle
Fight
Wings
PM me with all those goodies for sale when you get them, I'm still in the hunt for many of those classic covers and others.