Both Europa (around Jupiter) and Enceladus (around Saturn) have gas plumes and indications of liquid oceans. The situation is pretty well summarized here: http

Both Europa (around Jupiter) and Enceladus (around Saturn) have gas plumes and indications of liquid oceans. The situation is pretty well summarized here: https://www.nasa.gov/press-release/nasa-missions-provide-new-insights-into-ocean-worlds-in-our-solar-system https://www.nasa.gov/press-release/nasa-missions-provide-new... There is a mission in formulation for Europa (https://www.nasa.gov/feature/jpl/nasa-mission-named-europa-clipper https://www.nasa.gov/feature/jpl/nasa-mission-named-europa-c...) and an Enceladus concept called ELF.