When I inherited my aunts sewing equipment I found she used medical stitch cutters as stitch rippers, she had been a district nurse and a midwife for many years.
They are the best rippers ever, sharp,strong and good for getting into the tightest spots.
I have been carefully conserving her stash for years as I assumed I would never be able to replace them, then one day whilst browsing eBay I found a supplier and bought a dozen. That should be enough to see me out!