I have trouble to find the color vinyl sheets and transfer tape that are used in cutting plotters to make letters and stuff to stick to glass doors or whatever.

Where can I find those products?

There are 100's of companies that use them here, but they sell the letters, not the material. And I even I know what they use I look for retail quantities.

Just in case somebody with deeper knowledge reads this, I specially look for (shiny, single-) color material with a log tag. It should be removable without damaging the (paint) surface and also leaving no residue. Car wrap might work.

But the transfer tape seems harder to find.

Any hints?