Stalogy Writable Strip Stickies
Sturdy "film-like" stickies that are translucent so it shows text or drawings underneath.
Doesn't wrinkle easily, making it convenient for marking pages.
Sticks firmly due to large adhesive area but just like regular stickies removes cleanly so you can move them around or remove without damaging your notebook or pages.
For larger stickies with similar qualities, check out the Vellum Stickies