Toss up between sharpening stones and my brain. Sorry Mike, you have both in good supply. Can't help you justify a new purchase.
Can't do much without a sharp edge.
When I don't have the "right" tool to do the job I can figure out the best way to proceed with the tools at hand.
It may not be best practice but it may be the only way to get the job done.
Then there was the guy I worked with years back. Said he had two books that allowed him to accomplish any task.
Yellowpages (like I said "years back")
That should have read indispensable ”tools”. As my hand tool collection grows, and yes it’s still growing. I get a great delight from bringing tools back to life. They sometimes become indispensable for reasons that go beyond their use or their efficacy. That said, sometimes a tool becomes a department of tools. For example, a square. I have many squares, they have a specific purpose, they also match the scale of the work I’m doing. So there is a practical reason for having multiple squares. Mallets are the same, I have several mallets, different sizes and weights. They all have the same purpose but are scaled to the work at hand. I could go through the whole list and we would find that more or less that indispensable means many different things to many people. A really good question Mike, I’d be curious as to your list of indispensable. I’m always listening.
Yes, I think cluster of tools is perhaps more appropriate. My Starret collection gets very heavy use for layout and quality control. The Stanley hand planes are always employed when I am in the shop. I would not enjoy making dovetails without my Blue Spruce chisel. I make mallets, use them, give them away, wear them out, and make more. I have more dividers than friends.
But, I would have to say the workbench I built has grown to be my most used tool.