Intellij allows you to create custom TODO templates.
In the TODO window, click the filter icon> Change Filters> Add New Template.
As soon as you add a new template, Intellij will scan your project and add new TODOs to the list.
Official JetBrains TODO Example
Update:
According to the comments, I did a quick test, and it doesn't seem like you can scan TODO outside of the comments.
Jelle source share