What are the actions in Salesforce that don't invoke Triggers?

Hello Subhendu,

There are some system bulk operations don't invoke triggers. Some examples include:
Cascading delete operations. Records that did not initiate a delete don't cause trigger evaluation.
Cascading updates of child records that are reparented as a result of a merge operation
Mass campaign status changes
Mass division transfers
Mass address updates
Mass approval request transfers
Mass email actions
Modifying custom field data types
Renaming or replacing picklists
Managing price books
Changing a user's default division with the transfer division option checked
Changes to the following objects:
BrandTemplate
MassEmailTemplate
Folder
Update account triggers don't fire before or after a business account record type is changed to person account (or a person account record type is changed to business account.)

Hope it helps