The major examples are parts of the stdlib which offer higher-level pipelines (some answers here indicate the need for such things to be very flexible in their return values to allow this, but this is not a priori obvious - Java manages similar functionality with just the Stream<T> class after all).
In this (and the sibling pages in algorithm) nearly every entry is listed as either "template" or "auto" relhttps://dlang.org/phobos/std_algorithm_iteration.html