I remember reading them back in the early 90s (Robin Hood: Prince of Thieves, Far and Away, Back to the Future). They don’t seem to be a thing anymore (or am I just not noticing them).
As an aside I remember liking them but I was a preteen at the time so maybe they were terrible and I just liked the movies.
I read a Willow novelization and it gave back story to Sortia and I really loved getting more insight into her.