I make plant labels out of old blinds.They're easy to find ,people throw these out or use an old blind you have. You can get alot of labels from one blind.
As I am reading your post, I am making my labels using the P-Touch label maker which I will adhere to the mini-blinds.
I have found, however, that blinds marked with a Sharpie Marker, do fade in about a year. I'm hoping the label maker labels will last longer. The tape is designed for outside.
The best thing to write with IME is paint pens. They write about as well as 'fine' point Sharpies, and last practically forever. I've had some aluminum labels outside for 15 years that are still fine.
Craft stores should sell the paint pens. I buy the oil based paint pens. There are also water based paint pens. I have not tested them. I fold the blind in half and also write the name on the inside as an extra precaution.
I purchased a thin sheet of metal at a craft store, laid it on layers of newspaper or a phone book for cushion and took a ballpoint pen and embossed the name of the plant, and now I can use the paint pen to last forever.
I use plastic knives, cut in half. Agway makes an alcohol based marker that lasts far longer than a sharpie.
Old miniblinds are great, just snap-break them to size. I have found regular pencils outlast other markers.