Question about Attachments?
 

I found an open toed darning foot that's somewhat like this but it has a different area on the side of it for attaching with the screw to the machine, Could I use a foot like this on my singer 99-13 or would I need to purchase an open toed darning foot with a spring attached? What is the difference? Thank you!

https://brubakerssewing.com/wp-conte...07-AM.jpg.webp

The difference is that this foot will stay down as you are pulling your layers through, whereas a spring loaded one lifts up and comes back down over the layers. This one would probably be better for free motion embroidery over a thinner layer or darning over a thinner layer, where the jumping action would be more important for free motion quilting with the batting of a quilt. Just my opinion though.