Big Dog...Little Dog by P.D. Eastman
Fred and Ted are best friends even though they are very different from each other. An entertaining read that celebrates differences, sharing and working together. Two side notes: 1) There is a board book version of this story that cuts out several pages of the story, so it doesn't really make sense. If you go to get this book make sure that you get the full version. 2) My brother speaks some French, so a number of years ago my mom was super excited when she saw a copy of Big Dog....Little Dog (his favourite childhood story) in French and she bought it right away. When she presented it to my brother he was confused as to why she had bought him a book in Spanish. Lesson learned – you probably don't want to ask nana for help with your French or Spanish homework.
The Mysterious Tadole by Steven Kellogg
Every year Louis's uncle McAllister sends him an unusual birthday gift all the way from Scotland. This year he gets Louis a tadpole which he names Alphonse. Unfortunately, Alphonse doesn't grow into a normal frog, he doesn't stop growing and has an appetite for hamburgers that is more voracious than the Hamburglar. Eventually Louis's parents say that their apartment can't hold the tadpole any longer after he gets too big for their bathtub and Louis needs to find a new home for his friend. Since this is another classic there is the original version and a 20th and 25th anniversary edition, which apparently has new reimaginations of parts of the stories and additional illustrations. We've only read the original so I can't comment on which is best.