I've found that the clay soils closest to Lake Lewisville tend to be even less forgiving than the clays of Collin County and north Dallas, so I'd stick to hardy selections as much as possible.
Large: Lacebark Elm, the Oaks, Pecan, Bald Cypress, Southern Magnolia, Texas Ash
Medium: Shantung Maple, Chinese Pistache, Lacey Oak, Ginkgo, Teddy Bear Magnolia
Ornamental: Crepe Myrtle, Possumhaw Holly, Vitex
It all depends on what you're wanting and the size limitations. If there's insufficient room for a large canopy tree, yet sufficient room for a medium sized one, I'd go with a Shantung Maple, Lacey Oak, or even a Teddy Bear Magnolia (NOT a regular Magnolia or Little Gem).
My favorite 2 ornamentals are Vitex and Possumhaw Holly. Both are under-planted.