Allows a player to safely stay in one place while they afk.
The player won't be able to move or be moved, and won't be able to damage or be damaged.

Also, in config it's turned on by default that any hostile mobs that are unnamed, aren't in any vehicle and aren't being ridden
will be despawned upon leaving AFK around the player.

A fun addition for players to be able to scale themselves in-game to e.g. their irl height. (Metric system only)
Min-max height values can be changed in config.

Movement speed and block/entity reach do not get modified.

Only accessible by operators.
Lets you set a player's permission level without having to just yeet full operator on them.

• default - Regular player permissions
• moderator - Can use all commands that a command block can
• administrator - Can use all commands (except /smpperms), can not stop the server
• limited_operator (owner but fair) - Operator permission level but limited to only a few commands and tools essential (or so) for moderation
• operator (owner) - Regular operator permissions

Allows creative flight in any survival-like gamemode. Can be applied to other players.

Allows staff to disable individual damage types on the server. Resets after a server restart.

Allows to discard entities (No loot or EXP), removing blocks without them dropping anything and clearing inventories of entities and players.

/fill on steroids - works just like /fill but has options such as replaceOnly, destroyOnly, silkDestroy, silkDestroyOnly, fortuneDestroy and fortuneDestroyOnly
allowing staff to clear out or fill blocks within an area in ways that /fill can't.

A more fun way to "ban" people by sending them into the f#cking shadow realm.
A lot of safeguards and anti-abuse mechanics are in place so players can not escape in any way.

Banished players can still be killed if dealt enough damage in one hit (2^18hp or more)
this is so /kill still works if you ever need to use it in that dimension.

Harvest full-grown crops by just right-clicking them. Bigger harvest area when using hoes. Fortune does apply when harvesting.

Remove anvil's "Too Expensive" limit, with the highest EXP cost being 39 levels.

Shift-right-click a damaged or chipped anvil with an Iron Ingot or Iron Block to repair it a stage.
Iron Blocks have a much higher success chance than Ingots, and repair is always guaranteed by your 3rd attempt.

Allows modifying how many blocks a single piston can push.

Names of players that are invisible will be obfuscated in chat in death messages, whether they kill someone or die themselves.

Naming an Armor Stand "display" gives it arms automatically, posed for holding items and gear on display.

Naming Villagers or Tamable mobs "NoAI" will shut off their AI,
which is pretty useful if you want to reduce lag in trading halls or have a lot of pets that just sit around and do nothing.

Allows previously incompatible enchantments (different Protection types, Mending + Infinity, etc.) to be combined on the same item.

Shift-right-click an Enchantment Table with an Enchanted Book in your offhand and a regular Book in your main hand to duplicate the enchanted book, at the cost of some experience levels.

Some enchantments can go past their vanilla max level via an anvil (e.g. Sharpness VI, Unbreaking V, Frost Walker V). Fully customizable per-enchantment through tags.

More on BoostedEnchantmentLevels.md

(Disabled limit.....Speed keys mean it's enabled)
Individually remove speed limits for regular movement, elytra flight and vehicle movement to not be stopped by "Player moved too fast!" warnings.
This is useful for player cannons for transport.

All three speed limits (elytra, on-ground movement, vehicle movement) are removed by default.

Makes the time required to hold down right-click to use a riptide trident only 3 ticks instead of 10.

Allows players to pick presets of different species, mobs etc. via /abilities pickPreset <preset> that will grant them special abilities, debuffs and such.
Server moderators, admins and owners are also given options to manage everyone's abilities within /abilities command.

More on PlayerAbilities.md

Works around MC-271325 to prevent spam of;

[22:35:52] [Netty Epoll Server IO #5/ERROR]: Error sending packet clientbound/minecraft:disconnect
io.netty.handler.codec.EncoderException: Sending unknown packet 'clientbound/minecraft:disconnect'
[...]

in dedicated server console.
This will be removed when Mojang fixes it themselves.