Just about any of them that come in the green singer cardboard box. Just have to make sure it's short shank and not slant (that is for the 301). Older sets come with teh Tucker, newer sets come with the edge stitcher and gather foot. If you want both - buy two different sets. Probably cheaper than buying individual feet.
And then you can add the hemstitcher, and the zigzagger, and the guide foot, and the braiding foot, and if you really have a lot of money, the penguin (walking) foot.
BTW - the attachments can be addicting all buy themselves LOL!!
This is a set that I have for my 115. I matched them up with what was in the manual.
This is a later set with the updated selection (the others could be bought seperatly)
This is an older set I have for a 15 - they would all fit the 115 too. Those half circle looking things come in two sized, the smaller fits the 66, the slightly larger fits the 15, 115 and 201
And then you can get the Greist set - these are two that will fit Singers. However both of these have the underbraider and shirr plate for a VS machine, but the rest will fit the 115
