There are lots of alphabet-theme options for kids. I just ordered these cards for C-Man's room. I just love everything by Ida Pearle.
She has lots of other great pieces and will even do a custom name piece. If I were to get one for C-Man, I would for sure use this one of the boy with the train set. So, so C-Man.I also really like the art by Lorena Siminovich. You can find her on Etsy.
Jenn Ski also has some really fun stuff for a kids' room....I like her mid-century style.If I were to go for an animal piece, I like Manja Stojik.
Avalisa is another good option for stretched canvas art. Animal themes, "things that go," nature...whatever your little person is into...check their stuff out.
The good news is that all of these options are very affordable, so as the kids' interests change and tastes develop, we can swap them out as necessary.