Useful PCB stuff, ideas to order from PCB manufacturers

[honeybadger]

Hi,
from time to time I need to order PCBs from Chinese PCB manufacturers for my clients. Every time I see the DHL shipping prices (and the ridiculous DHL customs declaration fee) I add my personal projects $2 PCBs to the shipment. The thing is I am out of personal project ideas and I have far too much "perma-proto" breadboards already 

It seems wasteful not to use the $2 offer with "free" shipping. Custom SMD->DIP boards will be next. Do you have any other ideas which are actually useful to the electronics lab?

[BreakingOhmsLaw]

SOIC-8 to TO-99.  Haven't seen those around.
Not sure if footprints can be overlapped.