Top 10 Most Fuel-Efficient Hybrid Cars Published on May 20, 2019 in Top 10 by Frédéric Mercier Photo: Hyundai 1. Hyundai IONIQSurprise! The Prius is not the king of hybrids anymore. That title goes to the Hyundai IONIQ, which manages to burn a mere 4.1 L/100 km. By the way, it's also available in plug-in hybrid and electric configurations.