Now I have categorized all three of these women as “The Other Woman” not in the traditional sense of course. But in the sense that their best friend is the main protagonist of the show and the center of the group, and they exist outside of that role. Often their storylines get the second most amount of screen time and are of secondary importance. Now I will say right off the bat that this comparison is the stretchiest, I can draw some pretty strong similarities between these women but the results of their personality types are so drastically different.
https://vocal.media/geeks/new-girl-friends-and-himym

These three women are very different but every single one of them is the best friend of the main female protagonist of their shows. And These are the relationships that get the second most amount of screen time in their ensemble casts. Friends and How I Met Your Mother are obviously a much closer match in analysis. And though New Girl is somewhat different it still fits the sitcom archetypes that the other two shows were built around. I would eventually also like to discuss how these women interacted with their best friends because I believe that these shows (regardless of what you think about their overall quality) did an excellent job of portraying female friendships.