Today, both List templates and Task templates can only be used to create new items from scratch. There is no option to apply a template onto an existing list that already contains tasks or onto an existing task that already has subtasks, custom field values, and logged activity. This creates a significant gap for teams that need to standardize structures retroactively without losing historical data.

The most common scenario is a workspace restructure or process improvement where a team defines a new standard template but cannot apply it to work that is already in progress. The only workaround today is to create a new list or task from the template and manually migrate the existing content, which is extremely error-prone at scale.

The proposed behavior would add an "Apply template" option when right-clicking an existing list or task. For lists, this would import the template's tasks, views, automations, and custom field definitions into the existing list without duplicating tasks that already exist by name, while preserving all current tasks, time entries, comments, and history untouched. For tasks, this would import the template's subtasks, checklists, custom field structure, and description elements into the existing task, again without overwriting data that is already present.

In both cases, the system should offer a merge modal similar to how status templates already handle conflicts, letting the user decide how to resolve naming collisions, whether to remap dates on newly added items, and which template elements to include or skip. This would turn templates from a one-time creation tool into a living standard that can be applied, reapplied, and evolved across existing work without disruption.

This feature would benefit any team running recurring processes, onboarding workflows, or workspace migrations where retroactive standardization is essential but data preservation is non-negotiable.