A very common use-case in Lightning Web Component is iterating a list over an array in HTML file using for:each or iterator directive. Many times as a developer, we have to do something on the items based on user interaction. You would definitely require to get selected record id from custom iteration.
Lightning Web Component is the new way of building Lightning Components in Salesforce. There are high chances that you may end up with some common error.
Lightning Web Component has the ability to pass data from parent component to child component, but sometime you might need value change handler in child Lightning Web Component when the value is passed from parent Lightning Web Component.
Are you looking for adding or removing rows dynamically in Lightning Web Component to create records or do something else?
Are you looking for navigating to Lightning Web Component from another Lightning Web Component in Lightning Experience, Salesforce Mobile App? Using PageReference Object of Lightning
Are you looking for applying dynamic CSS Class in Lightning web Component?