Minecraft wiki entry for Tips_and_tricks, associated text: The most powerful rule in this respect is probablykeepInventory. Once set to true, players who die will respawn with their items and experience intact, instead of dropping their equipment where they died. This takes a lot of the threat out of "lava deaths", and also the Nether and End in general.
Another, less controversial, rule, is mobGriefing. This will prevent all mobs from breaking blocks, picking up items, or trampling your crops. Most obviously, this prevents creepers and Endermen from damaging your builds; it will also prevent mobs from picking up your items after your death. As a non-obvious side effect, it will prevent villagers from breeding, because they need to collect food to do so. It will also have significant effects in the Nether (Ghasts, Blazes, Piglins) and will drastically affect the late-game Wither fight, and the Ender Dragon battle.