Visual target selector builder: @a, @e, @p with limit, distance, volume, scores and tags.
Target selectors are short constructs like @a, @p, @e, @r, @s that pick out multiple entities at once using conditions.
Square brackets hold the filters: distance, entity type, biome, game mode, level, scores and tags. Several conditions can be combined.
The tool builds the selector and wraps it in a finished command so the output can be pasted without editing.
Pick the selector type.
Fill in the filters you need — leaving some blank is fine.
Choose the wrapping command and give its arguments.
Copy the finished command, and the bare selector separately if you need it.
@a selects players only; @e selects any entity including mobs and items. This is the most common reason a command "doesn't work".
A predicate filter restricts the selection by biome. A plains predicate, for example, selects only entities standing in that biome.
Volume (x y z + dx dy dz)
Scores
Tags
The selector can be pasted into any command that takes a target.