Boards A,E and F are all midgrade. There really are no values visible on the board. Most of the components are non-precious such as the fuses, resistors, capacitors and screw terminals not to mention the heat sinks. Midgrade board is selling at $0.35 per pound currently.
Boards B,C,D,G,H are going to be Peripheral Grade. While there are IC's on these boards, nothing really stands out as being overly valuable component wise. There are a few gold plated pin jacks with those ics helping the board out, but at the same time those are limited as far as value assistance is concerned. Peripheral Grade sells at $1.40 per pound at the time of this post.
I am including a link to our Material Database of actual "Backplanes" so you can see what one of those look like. They are not similar to any of these boards. Backplanes have multiple long card slots where gold fingered cards would plug into and virtually nothing else other than an occasional capacitor or ic chip.
Boardsort.com - Material Database: BackplanesThank you for the look!