Suggestions

Add a "Sell All" NPC to mine P

There's one in every other mine, but not one in P. There's no reason why there shouldn't be an NPC to sell all items in mine P.

Put quest rewards & bossfight rewards in /rewards.

I know that quest rewards go into your inventory on other servers but on prison we have /rewards, where we can claim rankup rewards and mining rewards. Quest keys from completing quests and boss keys from summoning/killing bosses should also be there. Earlier on I finished a quest but my inventory was full & I had chat turned off so I didn't see that I was going to get the quest keys and nev.. See more

/pseudo - change what pings you in chat

When someone says your name in chat, it appears green and you get pinged. I play on prison, where the top player is DGFallz, and sometimes i reference him in chat as DG. With /pseudo, DGFallz could change it so he would get pinged when someone said either "DGFallz" or "DG". I think this would be a useful addition and would let us talk to other players using their nicknames.

Chestshops

Chestshops are already on most other servers and should be on any server where players can own a plot of land. In prison you can have your own cell or visit other people's, and I think this would really help the player-based economy.

/is coop: More Options

There should be more options for /is coop, specifically to where/when players can be trusted, and to what degree.
Here's what I think should be added:

/is coop ALL gives every player on your island full access
/is coop <player> <x1> <z1> <x2> <z2> trusts players, but only in a certain area.
/is coop <player> TEMP trusts players for a certain period of time
/is coop <pla.. See more