I use No-Melt Mylar Template Plastic. cuts easily, but I use old scissors for it. Joann's has it, Amazon too. Plastic. comes in 12 x 18 inch sheets. (these days I just use freezer paper for my 6" all different blocks).

I will copy the template and then put laminate over it, which adds some substance and stability but still keeps it easy to cut. I will put a piece of two-sided tape on the back of the template if rotary cutting (the stickiness of the tape doesn't last very long). You will soon get used to how much of the template must be visible underneath the ruler. My alternate method is to copy the template onto freezer paper, and then iron onto the fabric so it stays in place.

I've used just about everything for templates, minus paper unless I'm paper piecing. I did make the investment and purchased some acrylic templates, hexagons, triangles and diamonds because as soon as everyone saw that I was making a Grandmother's Flower Garden quilt, they all want one to some degree. I use the Sure Grip dots to keep them in place while I'm cutting. When it comes to acrylic templates, though, you have to weigh your options. If the pattern you're working on is going to be the only time you visit that pattern, you best bet would be to use Mylar, milk jugs, cardstock and then use medical tape to keep them in place. If it's a pattern you're going to do several times, then it would be wise to get the acrylics. I'm not one that'll buy an acrylic template set and then never use it again, I feel it's a waste of money if it's only going to be used once.

I have’t found many quilt patterns for which I can’t find acrylic templates available for sale. I cut appropriate size fabric strips, then trace around templates with a mechanical pencil and cut out with scissors.

I still draw around some templates with a pencil and cut with scissors. old school. Good luck.

I use to buy a template material at the LQS near me some 25 years ago. I still have some of this template material that I use when I need to make odd templates. Most of the time I do not use templates anymore as my rotary cutter resolved that issue more than 30 years ago. I have started using a die cutter for odd shapes now and I love it.

If you use a paper template with the seam allowance marked exactly, you just line up the 1/4" on your ruler, with the seam line and cut. Doesn't matter if you trim a sliver off the paper template if you're always lining you the 1/4" line on the seam line. I use a paper template for my Big, Easy Dresdens. It seems to work better for me than drawing lines with a template, which adds the width of the pencil lead or pen. With a paper template and rotary cutting, I can accurately cut up to 6 at a time. If the pieces are all the same width, you can start with a pre-cut strip of fabric. That reduces two sides that you have to cut with the template.

I use the template material that "eparys" posted a link to - I line up the grid with the straight of grain of the template, and after I've cut the shape, I tape the template paper to the underside - this means the original markings are visible through the template. If needed, I use medical tape on the backside of the paper template. I use my rotary cutter to cut along the lines if it's a straight line type of template. So far, I haven't had to use a template for anything curved.

I have used foam backed place mats. No slippage at all. I draw around it and then cut. If a basic shape I can usually find an acrylic template to use a rotary cutter. i try not to use scissors to cut a lot, it will destroy your hands over time.