Avoid “The Wonky Donkey” at all costs. Unless you want to see a horrible example of making fun of those with disabilities. We got it as a gift. I read it once and trashed it. It was so offensive, I didn’t even want to donate it to our local Little Free Library.
We have a 3-year-old and also like “Giraffes Can’t Dance” in terms of learning about being more accepting of differences. I found the “Little Blue Truck” series good as well – no major social justice lessons, but LBT is friendly with all sorts of animals and helps those in need. The Maisy the Mouse series and Pete the Cat series also are good from the few books I’ve seen. My son was obsessed with “Brown Bear, Brown Bear, What Do You See” for long time and is now on to “The Very Hungry Caterpillar.” “Harold and the Purple Crayon” also is a bit trippy, which I like (and it got a reference in the TV show “Legion”). I have some minor issues with some of the little details in these books, but nothing major (e.g., the caterpillar is called “fat” but I think it’s done in a descriptive, non-judgmental way and it’s part of the process of him becoming a butterfly).
By the way, we have leaned towards the thicker “board books” these first few years since it was easier for us to turn the pages while holding him in one arm, and now that he’s older he can turn the pages himself.
A friend gave us “A is for Activist,” which is fantastic, but probably best for a bit older than our kiddo. Same thing for Ezra Jack Keats books – love 'em, and they will be great in another year or two.
(By the way, our only kiddo was born 6 weeks early and spent 10 days in the NICU. It’s a difficult, unexpected way to become a parent. He is now a smart, joyful little boy who still does things on his own timeline, regardless of how much stress or panic it creates in his parents. Best of luck to you and your family. 
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