Top 10 Most Fuel-Efficient Hybrid Cars Published on May 20, 2019 in Top 10 by Frédéric Mercier Photo: Kia 3. Kia NiroKia's small crossover is available in hybrid, plug-in hybrid and all-electric variants. Even with a standard hybrid powertrain, the Niro is remarkably efficient at 4.7 L/100 km.