I have always had my eye out for surplus electronics and one of the best finds I have ever had was this:
A local business was throwing away a very old Intergraph computer. This was a very large, old, and massive computer. It consisted of several cabinets of hardware, each containing circuit boards of standard TTL logic. The best part about these boards is the fact that every single chip on each of them is socketed.
This board in particular which is labeled as a "High Speed Concentrator" has over 550 74S, 74LS, and a few other miscellaneous chips socketed.
I really wish I had more information about this machine. This board labeled as "MPCB191 Bit Slice 2903 16 Bit Processor" has over 300 socketed TTL chips along with Motorola 68000 series processors.
If anyone has information about what machine this came from, please leave a comment. I am very curious about it. My only regret is that I didn't grab more boards out of the cabinet...