For over 50 years "accent plants" meant vinca vine, asparagus sprengerii and spike. But now there are many other plants that fall into this specialized category, and some of which you may know. Plants such as the sweet potato vine (ipomoea), licorice plant (helichrysum), lamium (perennial), lysimachia (goldilocks), glechoma & plectranthus (similar to variegated Swedish ivy) just to name a few.
You do not have to know them by name to want these plants, you just simply need to see them. Usually available individually but also on display in mixed combination pots and hanging baskets.
And how about blooming accent plants such as bacopa, diamond frost, bidens, lobelia, cuphea (Mexican heather) and brachyscome. These plants look great in any combination along with taller growing blooming plants like geraniums, begonias, impatiens, dahlias, etc.
But what about height? You do not need a lot of height in a hanging basket but in a floor/patio combination pot you do. Simple height is accomplished with the aforementioned spike but that could be considered boring, especially in a really large patio pot. You need oomph in your large pot so think bigger with cannas, angelonia, tall marigolds, tall salvia, dahlias or grasses. Think bigger still by using hibiscus or gardenia trees. Large geraniums or mandevillea plants surrounded by shorter, vining plants would also do the trick. Use your imagination and fill medium/large pots or hanging baskets with mosquito plants (geranium citronella) to wart off those pesky mosquitoes and add a little fragrance to your patio.