I think the most under acknowledged item in a shop has to be the roll of blue tape, and almost unarguably a must have. For me It has evolved into a dependency of sorts in so many different areas of woodworking and so much so that I can not imagine doing certain jobs without it. If I'm building a box for example that involves mitered corners the blue tape becomes my clamps, applying a piece across each joint, then with glue applied I close the box using one last piece to hold it all together. And with most of my applied moldings especially transition types this is always the clamp I use to tightly secure the molding to the surface until the glue dries. Even when I am doing things like prefinishing I will use this tape on the joints to ensure no finish gets onto the gluing surfaces. And I certainly can't forget about things like pattern routing, applying a piece to my template and another on my stock then with a couple of drops of CA glue directly on the tape I stick the two together. Personally I think this method works better then double sided tape, it certainly comes apart easier and has the added bonus of not leaving residue behind to deal with after wards, which has always been my experience with double sided tape. There are also more obvious things like it is really easy to write on making it a great way to mark individual pieces without directly marking on the project then having to deal with cleaning off all of those pencil or pen marks once the assembly is done. And of course there are a ton of applications around the shop like making start and stop marks on equipment such as a router table, just stick a piece down to the router plate and make your marks and when our done just peel the tape off leaving no marks behind to address. I'm pretty confident that I could go on for a while as to why I think blue tape is amazing but I think you get my point, it is definitely a tool in my shop.