Tools hidden on left column in InDesign.

Choose Window > Tools to restore your Tool panel.

You could also reset your current workspace: Window > Workspace > Reset [current workspace name]

Hi there,

Thanks for reaching out. Are you talking about the Toolbox?

I'd recommend checking out help article https://helpx.adobe.com/in/indesign/using/workspace-basics.html#manage_windows_and_panels to know Workspace basics.

If you are not able to get it back, try resetting the preferences using help article 

https://helpx.adobe.com/indesign/using/setting-preferences.html 

 **Please note that resetting preferences will remove all the custom settings and InDesign will launch with default settings. You can also take a backup of the folders in case you want to. Location is mentioned in the article. 

Let us know how it goes.

Regards,

Ashutosh