Here's a quick list of a couple commands that you can use to fend off against unwanted destruction in your vanilla Minecraft server. Whether it be creepers blowing up your house while AFK or you being dumped into the largest lava pit in the nether by a ghast.
1. You can use /gamerule doFireTick false to stop fire from spreading. This can prevent your wooden house to not get burnt to the ground when randomly struck by lightning, or a forest fire being started by a random lava pool.
2. With /gamerule mobGriefing false you are denying mobs that cause environmental destruction such as creepers or ghasts, to not break blocks anymore. Simple as that.
3. Are you the type to keep dying in random places? Tired of losing all your items constantly? Here's the solution for you: /gamerule keepInventory true, now whenever you respawn, you keep all the items you had when you died. This also saves your experience levels after grinding for hours on end at mob farms.
4. Personally, I get annoyed being shot in my back whenever I leave my base. With /gamerule doPatrolSpawning false, you have now turned off random pillagers spawning nearby to "patrol" your area.
If you know of any more ways to make a person's game easier by preventing griefing, drop me suggestions in our Discord and I'll add them to this resource!