Re Monopoly, there are also stories that Charles Darrow was influenced by earlier games which had a similar property trading element and which had been around for some years before he planned out his famous Atlantic City version and added the various trimmings such as "Chance" and "Community Chest" cards.
The latter, incidentally, have changed a little over the years, with some cards being dropped and others added. The British version also used variations in the cards (beyond just the conversion from dollars to pounds and the substitution of names).
The U.K. version was originally marketed here by Waddingtons. I'm not sure when they were bought out, but they were certainly still selling the British version of Monopoly in the 1970s (I have such a set, along with an early 1960s American version).