Sorry, just jumping in to add that you may also be interested in the optional :include/:exclude suffixes available to the fields operator. E.g. for my own wikis, I’ve defined a global variable,
\define systemFields() draft.title draft.of title tags text type created creator modified modifier
which lets me use the filter step fields:exclude<systemFields> and cut down on a number of ugly filters like that.
I only recently noticed this feature myself, so I thought I’d pass along the tip!