Helium-3

Helium-3 is a non-toxic gas. Touching it increases your jump height for a short time. It can be found on some Gas Giant planets in infinite quantities.

Warning: you can't swim in Helium-3 (unlike many other gases). If you are exploring the Gas Giants by swimming, then entering a layer of Helium-3 will cause you to rapidly fall down. This can be very deadly (if you don't have anything that grants fall damage immunity - Parasol, Ighant Bulb, Oddball Sphere tech, etc.)