Ok, so I am so excited that I can't keep it in. I put together a complete list, including publish dates, I just have to tell y'all.
* means 1st printed Edition
** means Autographed Edition
Black Beauty - 1828

Smoky, The Cowhorse* - 1926
My Friend Flicka* - 1941
Thunderhead * - 1943
Misty, The Chincoteague Pony * - 1947
King of the Wind * - 1948
Sea Star** - 1949
Born To Trot ** - 1950
Old Yeller* - 1956
Summer at Horseshoe Ranch*-1957
The Frosty Filly* - 1961
Savage Sam* - 1962
Storm, Misty's Foal* - 1963
Horse of Two Colors* - 1969
Gentle Ben - 1970
The Dog In My Life -1971
Summer Pony* - 1974
Winter Pony* - 1975
A Horse Like Mr. Ragman* - 1977
A Dog Called Kitty* - 1980
Beauty* - 1988
The Backwards Bird Dog* - 1997
I plan to add First Editions of
The Red Pony
Comanche Moon 1 & 2
The Virginian
Streets of Laredo
If you can think of any more let me know.