First, make sure you buy the correct rulers made specifically for quilting with a mid arm. They are much thicker than cutting rulers. HQ makes many rulers themselves and they are pretty good. Also when searching on line they are often referred to as quilting templates.
My favorite, most used ruler is a small straight edge. My two most favorite straight edge rulers are only 2" wide and one is only 6" long and the other is only 7" long. They both have laser etching for lining up spaced inervals of 1/2", 3/4" and 1" as well as 45 and 60 degree angles. I use my small straight edge rulers more than any other ruler. I don't like handles so mine are simple and flat with no cut outs or handles. I do have an HQ straight edge that is larger and I never grab it as it is too unwieldy for me to manipulate due to it's size. I think pretty much all the manufacturers are the same when it comes to quilting rulers, just make sure they have the etched markings you want and are not too big.
My 2nd most used rulers are my curved rulers from The Quilted Pineapple. I have the full set of the original 6
https://thequiltedpineapple.bigcarte...by-linda-hrcka but I have yet to use the 10" one. The others I use pretty regularly and I use them to draft quilting designs as well as to guide my quilting.
I have a set of circle templates too but I don't use them a whole lot but am very glad to have them when I do need them. I don't use any of the specialty rulers like ones that make special shapes like clamshells (I prefer a circle ruler for that). I only have a couple of specialty rulers and haven't used any of them.
So it really isn't so much what make to buy as most who make quilting template rulers make them to the same specs. It is what shape. If want to get started with ruler work I would recommend just getting a straight edge. If you like doing ruler work then expand to other shapes and sizes.