The Westalee 6-piece beginner set is my go-to set. The price is actually really good when you buy sets. I also have a few Amanda Murphy sets. Every Circle, Every Oval, Every Wave, Every Ribbon Candy and Lollies. I use all kinds of circles and ovals, so the sets are versatile. I also use the waves a lot. If you can join a Handi Quilter ruler of the month group, the rulers are a good price. I've done a couple of these. The club that just started is all for borders. Looks like a good one.
My favorite gripper for the back is Handi Grip. It's clear and holds better than all the other things I've tried.