Close to My Heart has added so many punches with this last Idea Book and they are super fun.
This is a corner rounder (Z1912) and I use mine to not only round corners, but to also do a scallop edge since I don't own the scallop border punch.
Here is the Scallop Border Punch (Z1851), an item I don't have. I have chosen not to get this punch or the other two border punches because I have a Cricut Expression that I use when I want a funky and fun border. If you don't have a Cricut and you aren't planning on getting one any time soon, then this border punch and the other two are probably perfect for you. Here are the other two border punches:
This is the Chevron Border Punch (Z1998).
This is the Triangle Border Punch (Z1997).
This is a fun punch and I love mine! This is the 1 inch circle punch (Z1999) and even though I have a Cricut I have one of these because I love circles and cutting a whole bunch of circles with the Cricut is kind of a pain, especially trying to get all of those circles off the Cricut mat, so I use this circle punch instead. Plus I can use the circle punch to punch out things that I have already stamped, which is really hard to do with the Cricut.