A modifier takes one series, such as an indicator, price or another modifier, and turns it into a new one. Smooth it, rank it, measure how fast it's changing, look back a few bars. They're small, and they combine well: the percentile rank of Bollinger Band width is the whole idea behind a squeeze filter.
Two notes before you reach for one. Modifiers take series, not the output of a Math or Logic node. And for two common jobs there's now a better node: the Crossover for crosses, and Price History for levels like the 20-bar high.
Bars Ago
A series' value a set number of bars back.
Moving Average
A simple or exponential average of any series.
Percentile Rank
Where the current value ranks in its recent history.
Rate of Change
How much a series changed over a period, in percent or points.
Rolling Min/Max
The lowest or highest value of a series over a period.
StdDev / Z-Score
A series' standard deviation, or how far it sits from its mean.