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.
I have a favorite seam ripper. The blade is one end and the other is a curved point that is ideal for poking out corners, flattening seams, etc. I use it more than I care to admit 😀 but when you need to try again there is nothing else that works as well.