I like to do watercolors and my "collection" changes over time. I wanted a system that would enable me to not put 1,000 holes in a wall.
So... I looked at finished picture rails --- WOW! they can be pricey!
Since it's CV19 isolation time, I got productive with the boards that I had purchased weeks earlier! ...and I am VERY pleased with the results! ...and I did it all by myself! -- Win!
(I initially started my display wall with monofilament that hung from the top of wall and had slide "hooks" down the length. This did not work well, as the pictures were always wonky -- and even Museum Mud stuck on the backs would not hold to my stippled walls.)