I mentioned Andy Devine yesterday, and that got my train of thought chugging along to Roy Rogers and all the sidekicks he had in his 111 movie and TV roles. That number isn't very accurate. On IMDb, Roy is listed as a parade rider in the Tournament of Roses parade in 1954, and he also appeared in many Sons of the Pioneers appearances. These should have been separated out into the "Self" category.
Andy Devine played Cookie Bullfincher in nine Roy Rogers films in 1947 and 1948. Of course, the stories varied, so Cookie was a constable, a doctor, or a judge...or just a sidekick. I think Andy is remembered better for his role as Deputy Marshall Jingles P. Jones in "The Adventures of Wild Bill Hickok" in the 1950's starring Guy Madison. He was sometimes referred to as Jingles Devine.
There was also George "Gabby" Hayes who made a total of 194 movies. 43 of them were with Roy, but not always as his sidekick. Roy and Gabby appeared in Dark Command with John Wayne in 1940. Gabby probably thought that Wayne was a young whipper snapper. It is interesting to note that Gabby was one of the best dressed men in Hollywood, despite his rough appearance on screen.
Let's mention Pat Brady. On the "Roy Rogers Show" he didn't have a horse. He drove a Jeep named Nellybell. Brady played in 71 roles, from 1937 to 1963. He was also a member of the Sons of the Pioneers, so his actual acting roles may be somewhat less.
Smiley Burnette was in nine Rogers films including one of the best, King of the Cowboys from 1943. In Burnette's 56 years, he appeared in 153 roles, ending up on "Petticoat Junction."
Those four were Roy's most popular sidekicks, but he had many more. I think Gabby was my favorite. He also appeared as a projectionist in Pick a Star from 1937 with Laurel and Hardy and a host of other stars, although he in unlisted for that film in IMDb.
I suggest that you take a trip to your local Walmart. Near the checkout lines you will find boxes of DVDs for $1 each. Many of these old "B" westerns are in those bargain bins. I found King of the Cowboys and My Pal Trigger for a buck each, and they are now in my collection.