The best replacement for hydrogen is helium.

The best alternatives to hydrogen are rated as following:
★★★★★  helium
★★★★★  gasoline
★★  boost
★★  electric cars
★★  atomic bomb
★  electric car
★  carbamide peroxide
★  ethanol
★  oxygen
★  covalent bonds
★  helium lighter
★  deuterium
★  fossil fuels
★  nuclear bomb
★  hydroxide
★  helium balloon
  atom bomb
  fossil fuel
  nitrogen
  helium lifting power
  nuclear
  petrol
  hydronium
  fuel cells
  helium lift
  hho
  helium balloons
  synthetic fossil fuels
  batteries
  petroleum
  atomic bombs

Your alternative for hydrogen is not listed? Suggest!
Speaking about hydrogen, one probably shouldn't forget about neutron.

Other search terms related to hydrogen and their ratings are:
★★★★★ neutron
★★★ glowing splint
★★ fluorine
★ oxygen reaction
★ copper oxide
carbon dioxide
You have in mind a companion for hydrogen and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of hydrogen in all years. Click on graph for more.
hydrogen
helium
gasoline