"Régence" sets are called after "Café de la Régence", the famous chess café in Paris from 1718 till 1910 when it became a restaurant. In the café they used this type of set. Main difference with "Directoire" sets is the figural Knight. Note that Keats and some others call these sets "St.George".
The "Régence" sets have been produced from a bit before 2nd quarter 18th century till even today. It was the most widely used pattern, certainly at the continent, as standard before the "Staunton" sets took over. In 1924 the FIDE declared "Staunton" as standard for their tournaments as well, after which the "Régence" style was used less and less.