Salvage Ideas You may not have thought of. Repurposing Junk
Of course you can use the components in a way consistent with their original use, but :
Use upside down, solder components to the headers, that is the bottom of the header that was soldered to the board is soldered to the component. Then insert the component into a prototyping solderless board. The component makes much better, easier connection than just using the component leads.
Hard Drive Cables
Use any time you need many many connections and would like to be able to unplug the connection. Additionally you sometime find components like LCD displays that will plug into cable. I usually cut the cable and use only one of its plugs, soldering the connections on the other end. You can also reduce the width of the cable and/or plug ( although the plug will be weaker and may need reinforcement.
Keyboard Cables and Plugs
I get quite a few Keyboard Cables and Plugs, but until recently did not know what to do with them. Then I had a flash – I build a lot of things, but do not really want to deal with a power supply. Why not have one central power supply and plug in each project. I took 3 dual keyboard ( and mouse ) plugs and wired them in series. The supply ( again from a computer ) provides +5 volts and + and – 12 volts. This is good power for most of what I do. The cables are soldered into the project and plug in when I need power. The only limit is that I would keep the power to a few hundred ma.
Computer Power Supplies as Bench Top Power
Lots of projects published on this, here are a few: