The beloved favorite of shops in the US has always been Rice's Silamide and it's expensive and sold in amounts WAY too much to be practical for the average home sewer. I know theater majors who talk about this stuff with open lust as being out of their department's budget. If you love theater and want to improve shows you personally see, spring for some of this stuff in bulk and watch the costume room faces light up in your beloved theater.
Because your secret is it is sold in every major beading store probably in the nation in small 40 yard stock cards you can buy for $1-2 including some lovely samplers for $9 on Etsy, Overstock, etc. which offer a dozen major colors for under $10. This and a couple of good needles is all you need to do the repairs I'm going to show you over the next few weeks. No fancy machine. No breaking the bank. No hours laboring to create the perfect x or y.
online) for the fussy fabrics or when they want beautiful invisible stitches. Great stuff silk thread. Strong. Flexible. Made to last. It's been used by every major culture to my knowledge for thousands of years because it works. Everyone always mentions the needle as their weapon of choice, but for me it's thread. Well, I'm off to do some spring cleaning. Happy St. Patty's Day.