Minihud
Every feature is allowed
Litematica
Every feature is allowed, with the exception of specific EasyPlace mode features, such as the ability that allows you to place blocks in mid-air.
Render Invisible Entities is allowed but is prohibited during PvP events.
Item Scroller
Every Feature is allowed. (But please don't go too nuts with the mass Crafting, the game will kick you for sending too many packets)
Tweakeroo
Free cam mode is allowed when used to look inside redstone machines (and for similar uses). It is not allowed when used to gain an unfair advantage, such as (but not limited to) its use to aid in mining or while searching for caves.
Using it for videos on the server is allowed.