Oh yeah, all the time.
I'll change the names of the monsters (or just change the tilename to 'Monster1,' 'Monster2,' etc. in Roll20) so that they have to rely on my descriptions to figure out what they're fighting. I create my own magic items, and heavily embellish others (a common longsword +1 is described as the Blade of Ballenroe, a steel longsword with the crest of the Ballenroe family in the pommel.) In my game world, the dead are embalmed before burial, so most corporeal undead look identical to mummies. My dragons are all gray, and have the chameleon-like ability to change the color of their scales--no way to tell what it's breath weapon is going to be from appearance. And so forth.
Basically, I want to eliminate the 'gamist' attitudes and behaviors at the table as much as possible, so that we can focus on immersion. In a perfect gaming session, my players forget they are even playing a game at least once.