Minecraft wiki entry for gamerule, associated text: To stop the day-night cycle: gamerule doDaylightCycle false
To stop natural healing: gamerule naturalRegeneration false
To stop creepers, ghasts and other mobs from modifying blocks: gamerule mobGriefing false
To stop the natural cycle of weather: gamerule doWeatherCycle false
For the player, so that they can keep all of their valuables when they die: gamerule keepInventory true
To stop TNT from exploding: gamerule tntExplodes false ‌[BE only]
To stop command blocks from showing what they do: gamerule commandBlockOutput false
To stop phantoms spawning:gamerule doInsomnia false