The yii2-detail-view extension offers you an easy way to EDIT and VIEW your model data, toggle these modes, and adds other features. You can read the extension documentation and/or view a demo of this extension, to understand usage.
The yii2-field-range extension enables you to easily setup ActiveField range fields with Bootstrap styling. You basically can setup two attributes joined together like a single field with combined validation error block.
If you are coming over to Yii 2 from Yii 1.x, you may have already read this useful wiki for creating dependent dropdowns.
You can use a similar approach in Yii 2 to do the same. But if you are looking at a prebuilt solution that helps you manage it easier, read along.
You may have scenarios, where you want to store a specific array configuration to the database. A classic example could be saving Yii widget configuration to the database and then retrieving it at runtime, with dynamic parameters set. This wiki discusses one of the approaches to do this. Let's consider you have something like the NavBar configuration below to store in the db: