The only gel I know of that does this is Dif. It is pretty much the same as the concentrate but it sticks to the paper better. You can put it on with a brush or a roller.
I question the 'no tiger' idea for hard to remove paper. I've removed wallpaper in nearly every room wall (and some ceilings) in my house. I have used both types of Dif. I never would have gotten some of it off without the paper tiger. And I used the gel.