Sharepoint - Clear list items and reset id back to 1
Unfortunately, you can't truncate
the SharePoint list as you do in the Database Table!
Also, I don't think it's a practical solution to
- Delete the 100 lists then recreate it again or
- Save 100 lists as a template without content then delete the original list then recreate it again!!!
In your scenario, from the beginning, it was supposed to create a SharePoint solution/add-in for all lists definition. Once you have finished the testing phase, just redeploy your solution.
To create A-list Definition
List definition / list template in the SharePoint add-in model
How to: Create a Custom List Definition
The only way to reset the ID to start from 1 again is to delete the list and then recreate it.
One way to reset ID in a SharePoint list is that you can save list as template and then use this template to create the list again. The ID will be reset and start from 1.