We use labels from Zebra. We use the Zebra ZT410 printer.

Z-ULTIMATE 4000T HIGH-TACK WHITE.

Premium white gloss thermal transfer polyester label with a high-tack permanent acrylic adhesive. Ideal for applications that require up to 3 years outdoors, resistance to moderate chemicals and temperature exposure up to 300⁰F.

They come in rolls of 4300.

And to remove them we have to scrape with razor blades, and then use Rubber Cement Thinner to take off the stickiness. I know, it sounds weird, but it works really well. Use in a well ventilated area. :) 

Thank you @Cozmo03 ! This will definitely be helpful for others as the school year starts