I have had a Glow-in-the-Dark G2 colouring book since my childhood. The outlines of the pictures glow...until you accidentally go over the edges with a felt tip, then that ruined the glowing effect. Quite annoying for a young child who's trying desperately to colour neatly without much success!
I still have my two (I had one which I actually coloured, then we got another one later on so I could "keep one for the collection"), and remember them stacked high at the garden centre where we bought them. But I've never seen one come up for sale online.
I wish I'd bought more of them back at the time!