An aggregate handlebars helper is a custom function for performing calculations, such as sums or averages, on a collection of numeric values, typically within an array in your JSON data.
The built-in variables apply within handlebars helpers to give you access to metadata and contextual information, primarily used when iterating through records with block helpers
Logic-check handlebars helpers are custom functions that evaluate a variable or expression, and allow you to control execution based on a true or false outcome
Miscellaneous handlebars helpers are a category of custom functions for requests like generating AWS signatures, returning field values, and referencing lookups