Minecraft – How to allow other players on the server to use commands like teleport, but not spawn in items

Yes, there is a way in the 1.8 snapshots.

Using a RedStone clock give all entities that damage the player a huge weakness effect:

/effect @e[mob id] 18 9999 127

Note that @e targets players and thus so that only mobs get a weakness effect you have to put in an ID for the entity type. You will have to have a few command blocks each for each type of hostile entity(One each for zombies, skeletons, endermen, creepers{change gamerule doMobGriefing to false}, zombie pigmen, ghasts and blazes). This prevents them from doing damage to the player. Note also that if you give them a weakness level of more than 127, it has a negative effect, meaning it will give them basically 127 strength.

Another method that can be used in 1.7.x is giving all the players a resistance effect like you did but weaker, and then giving players a strength effect that overpowers the resistance.
Strength:

/effect @a 5 9999 6

Resistance:

/effect @a 11 9999 4

This will give all players resistance 4 and this is enough to make them invincible to mobs. They will still take hits but will not take any damage. Note: I am not actually sure if Strength 6 is enough to overpower Resistance 4. If it isn't, just give a higher strength. If the Resistance is too low, give them a higher resistance and higher strength. Just look for the balance. :)

A few questions:

1. Is there a reason you are not making it on Peaceful mode? (I imagine it is so that players don't regenerate health that quickly but you can turn the gamerule naturalRegeneration off)
2. Is there a reason, if you don't want to turn it to peaceful, why you want to keep gamerule doMobSpawning on?
3. Are you manually spawning the mobs, i.e. with command blocks? If yes you can modify their attributes to not allow them to damage the player.

So yes, there are ways to do it in vanilla Minecraft.

Hope I helped!

As described here (http://www.mcmodder.net/still-hungry):

Install the Forge API. Run Minecraft at least once. Put the mod’s .jar file in the mods folder located in your .minecraft folder. For any additional info, head to our big Mod Installation Guide. Ready to go! Enjoy.

On the Mac, the .minecraft directory is located in your user Library folder, which is hidden by default. You can get there by clicking Finder in the Dock, pressing Cmd+Shift+G and entering ~/Library/Application Support/Minecraft