Washi Tape
Washi (wikipedia.org) is traditional Japanese paper made from the inner bark of one of several plants including the paper mulberry. It is strong but easy to work with and incredibly durable.
A high-quality washi tape can be used like the western "masking tape" I’ve used my whole life, but is so much more pleasant to work with that I find myself using washi tape all the time.
I first started seeing washi tape used for decoration for journaling and scrapbooking. It comes in a huge variety of colors, printed designs and clever border patterns.
Just so you have a point of reference, I’m currently using "mt" brand washi tape. It’s made by Kamoi Kakoshi Co., Ltd. from Japan, which was established in 1923.
Whatever magic adhesive they’re putting on this stuff is amazing - it’s strong enough to hold really well on a multitude of surfaces, but peels back off with zero residue and can be re-used dozens of times. It’s not cheap, so I tend to use little pieces, which means a tiny roll lasts a long time, making it a better value than a cheap tape that is less pleasant to use, doesn’t hold as well, and can only be positioned once.
Oh, and I can’t resist showing off this incredibly incredibly cute Sun-Star brand "cassette tape cutter":
As you can see, it looks like an audio cassette and holds two rolls of washi ready for dispensing. I’ll admit that I bought it because I thought it was really cute and clever. But I am amazed at how often I actually use it.
The design is brilliant. The tape cutters work great. It’s surprisingly nice to have two different colors or designs on hand. And loading it is easy because it opens up like a book. I am absolutely not being paid to endorse this product, I just love it.