Do you have any tool that you use all the time? Do you recommend it to everyone unprompted? Is it ridiculously specific to your situation, wants and needs? Let every one know how they can make their sewing better!!
I myself don’t have any at the moment, but I have been eyeing a nice pair of left-handed fabrid scissors for quite some time and I might get it some day.
Something I always feel especially glad to have is those tweezers with the bent ends on them. I use them to thread the machine (especially pulling through from behind the needle), pull up bobbin thread, turn edges under close to the needle, grab stuff that fell behind the desk…. I can’t think of all their uses right now.
Now that you mention it, I regularly get the tweezers from the bathroom (with appropriate cleaning betwen uses of course), I should probably get some sewing tweezers.