I was playing Minecraft often in past days, and once again have came to thoughts that start from phrase "I wish there was...".
As result, I've got to 'playing around' with source of Zombe's ModPack.
This mod already adds some nice additions for single-player and survival multi-player, and most of my edits turned out to be experimental, or something that only I might see use of.
So, these are...
2021 edit: oh man, none of the images work anymore, and they aren't even on The Internet Archive! Here are rough equivalents that I could find in archives:
Entity radar
I added enough stuff that many modpack settings menus required pagination
WorldEdit-style region operations for automatic building/digging.
Original post continues below:
Item highlighting
With right configuration, can even tell what tier the items are.
Serves primary purpose of finding your death location, along with making it possible to efficiently scout open areas for items remaining from monsters/other players.
Fog control
Effect (turned off / turned on)
Has the largest use if trying to find objects in water, lava, or near bottom of world, where additional black fog applies.
Toggle-able sneak
Can be considered very valuable for navigating sectors consisting of floating islands or unsafe bridges.
Since effect not 'wear off' while typing text or interacting with objects, it can be efficiently used for a lot of silly and\or cunning activities.
Toggle-able running
Possibly the only way to see your character running not from front\back.
Useful for getting over large distances without any dangers or major obstacles.
Personal use involves combining this with a not-well-known bug and coordinate scaling to travel over extreme distances via top of 'Nether' world.
Hotkeys
Nothing to show here, but in short these are bind-able single-line chat messages that might be used too often to type them manually each time.Chat "API"
Seemingly self-constructing 'parkour' challenge.
On screenshot, WorldEdit plugin is utilized to construct a circular ladder from platforms.
Commands are generated by earlier mentioned 'framework', now ported to GameMaker and Lua.
In contrast to previously used method of interaction with the game, this does not require window focus, and is only limited by server&client's ability to handle incoming text (in case of WorldEdit, sending lots of world modification commands will force additional updates for all nearby players, causing additional server load).
Overall, interesting ways of wasting time.