I did this pretty quickly but from what I can gather these are the least painted Bob Ross paintings of 2021.
Wilderness Trial (S30E4), Double Oval Fantasy (S16E5), Mountain Mirage Wood Shape (S16E4), and Misty Forest Oval (S14E12). These four paintings we're only done twice each over the course of 2021
Mild Winters Day (S17E6), Back Country Path (S243,E7), and A Warm Winter (S28E2). These three paintings were only done once each over the course of 2021.
Double Oval Stream (S25E4) and Splashes of Autumn (S25E4). These two were not painted at all over the course of 2021.
For me personally I did Splashes of Autumn but not until the calendar hit 2022. I did paint Back Country Path, Wilderness Trail, and Double Oval Fantasy last year. I think people mostly avoid certain BR paintings due to the prep work involved. For instance it makes sense to me that the double ovals, and the wood cutout were among the least painted. Most people just want to put the canvas on the easel and start to paint.
The other reason people avoid certain paintings, I believe, is they just aren't as attractive paintings as the rest of Bob's work. Some of Bob's are kind of ehh, blah. I try to liven up his dull ones the best I can but can't always make miracles happen, lol.
Hope the community finds this interesting.