My mom is a great fan of Kate Greenaway. Between us, we own hard copies of nearly all the titles listed below. But luckily for all of us, much of her work is available in the public domain. Her illustrations are soft and charming, without being overly sweet. Sometimes she collaborated with others, sometimes she worked alone.
This is her collection of Mother Goose stories.
Here is her alphabet primer, A Apple Pie. Each letter has an action associated with it. Well, until the end, when it gets a bit silly.
One of her earlier books was Under the Window: Pictures and Rhymes for Children
Slightly later came Marigold Garden, Pictures and Rhymes. Both of these feature rhymes which are sometimes a bit goofy and trite, but the pictures are lovely. And really, they’re designed for little kids, so it’s your voice that matters when you read them and LOOK PRETTY PICUTRES! Er, um…
The Pied Piper of Hamelin, with Robert Browning, has some exceptionally detailed illustrations.
The “Little Folks” Painting Book, created with George Weatherly, was designed as a coloring book. The version linked here has had nearly all of the plates painted in, simply but skillfully.
You can seek out more titles by Ms. Greenaway with a search for her at the Internet Archive, but I would like to point out one more, much lesser-known title: Language of Flowers. Most people know that a red rose means passion, a white lily indicates mourning, and daffodils are a general way of sending regards without any further sentiment. But what about dried flax? Someone sends you a bouquet of Dogsbane, flytrap, and almonds, just what exactly does it mean? Well, now you can look it up! The flowers and plants are all listed alphabetically, with illustrations dispersed throughout.
You can also see a tongue-in-cheek post put together on the modern language of flowers over here at Food It Yourself.