I like so many of them, but black has always been my favorite as long as there's been alternate colors <3
I really like black animals irl and in games that have them, if any animal has a black variant I'm all over it LOL
Blue Yoshi, because in Super Mario World Blue Yoshi can eat any shell that can make him fly. Its so OP and you'll get through the levels no problem. Well except for auto scroll levels which I know is a real pain to go through.
I love them all, but I’d say maybe purple, blue, black and green. I have only played a small handful of games yoshi was in and probably not the ones those colors were in, but judging by the color alone, I like the darker color yoshis. Purple and blue are my favorite colors; I mention green because I’m pretty fond of him. My sister, some of my friends at the time and I used to fight over who played as Yoshi in Mario Party (the original N64 one).
The light-blue Yoshi is probably my favorite just because light blue is one of my favorite colors. I'm also a fan of the classic green Yoshi and the black Yoshi as well.
And as a fan of Yoshi's Woolly World, I went through the list of Yoshis from that game and these are some of my favorites: Yogurt Yoshi, Cotton Candy Yoshi, Wii U Deluxe Yoshi, Nighttime Yoshi, Naval Piranha Yoshi, Nintendo 64 Yoshi, Alpine Yoshi, Glacier Yoshi, Star Yoshi, Sunset Yoshi, Bubblegum Yoshi, Spooky Yoshi, Painty Yoshi, Baby Bowser Yoshi, Silver Yoshi, Gold Yoshi, and Shiny Platinum Yoshi!
There are a lot of colors that I enjoy, but I would have to say that my preferred yoshi color is purple. The color purple is very easy on my eyes which is why it's my favorite color. However, when I play super smash bros ultimate I choose the wooly yoshi because I like how the texture looks on them.