What is it?

An unofficial port to newer minecraft versions of original Bucketable by blockerlocker

What does it do?

Here is a copy of snippets from blockerlockers description:
Bucketable allows you to bucket any mob you want! Whether it's as simple as scooping up your pet frog, or as ridiculous as entrapping an entire Ender Dragon in a tiny metal prison, you can do it all!

Tutorial

To bucket a mob, simply hold a water bucket, look at it, and right click! Any mob that has some other function when right clicked (ie; villagers, camels, allays) require you to sneak while right clicking to bucket them. Then right click anywhere on the ground to empty the bucket out!

Commands

Bucketable comes with several presets that only enable bucketing specific groups of mobs, as well as the ability to completely customize exactly which mobs you want to be bucketable.

Enables all mobs:

/function bucketable:presets/all

Disables all mobs:

/function bucketable:presets/none

Enables friendly water mobs:

/function bucketable:presets/water_mobs_less

Enables all water mobs:

/function bucketable:presets/water_mobs_more

Enables small mobs:

/function bucketable:presets/small_mobs

Add a specific mob:

/function bucketable:add/[MOB_ID]

Remove a specific mob:

/function bucketable:remove/[MOB_ID]

See all enabled mobs:

/function bucketable:list_enabled

In-game help menu:

/function bucketable:help