I think maybe just some color matching games. My son doesn’t know colors that well. But he can match colors pretty well with games. Maybe get a color game that had just color. All the same shape or animal but different colors. To help match that instead of other things. Like we have a game that’s color matching but also shape matching. Or color matching with dinosaurs but it’s different dinosaur. So maybe try just a color game. But it might also take a little bit once he learns the color names. So maybe try that and see if he can match and say the names
There are tests you can find online! They might be too advanced for his age though, unless he's able to recognize numbers. Those are the most common ones I've seen. Red green color blindness is most common and blue yellow is the second most common. I'd do a red green test first. Also keep in mind that colors are confusing! My daughter has the basics down but she definitely gets confused at times.
They have color blind tests online that have animals, shapes, and numbers. My oldest is color blind and I googled one of those tests before taking him to the doctor just to verify. There’s nothing really you can do but it’s good to know! My son was getting in trouble with his art teacher for using the wrong colors because she wasn’t aware he was color blind.
He turns 3 at the end of March ***