Ceramic planters like these once brimmed with flowers and greenery on windowsills. In the 1930s, '40s, and '50s, florists stocked these vessels in shades of green, yellow, white, pink, and blue, in styles from classical to Art Deco. Now they're mostly relegated to attics and basements, where they hold only dust. As a result, you can find them often at prices from $5 to $30. Use them anywhere you need a colorful set of containers. Many bear the names of well-known potteries, such as McCoy, Ro...