Uhm, click here?

Garret submits a slip of paper "Yes - Garret Kozrok"

https://www.spigotmc.org/resources/jukebox-music-plugin.40580/
(This requires https://www.spigotmc.org/resources/noteblockapi.19287/ to use)

Something that would allow for /range and you are able to see the distance to a location you are seeing posted in the chat. 

Radius effects so spirit guardians and other effects could be measured well, same with cones maybe, not sure where to find there. 

/Walkspeed to allow for players to change the speed they walk at. Helps for movement in rp

/sethome /home, all that jazz would be amazing.

/echest /enderchest to access the enderchest wherever would be incredible

https://github.com/Feikovandijk/ArtMap (This is a art plugin that allows people to draw ingame, could be really cool to see.)

https://www.spigotmc.org/resources/big-doors.58669/ Big doors is quite swell, its in the name but allows for some different door types.

Already suggested this one in discord, but I'll throw it in here too, its real interesting. https://www.spigotunlocked.com/resources/realisticseasons-1-16-3-1-20-3-seasons-in-your-minecraft-world-with-temperature-and-calendar.290/

All of these are like, unnecessary but they would add something for a lot of people.