Magento2: Cart events
Below Are the list of Events for cart :
- checkout_cart_add_product_complete
- checkout_cart_update_item_complete
- checkout_cart_product_add_after
- checkout_cart_update_items_before
checkout_cart_update_items_after
checkout_cart_save_before
- checkout_cart_save_after
- checkout_cart_product_update_after
For Use of each refer this url - https://cyrillschumacher.com/magento-2.1-list-of-all-dispatched-events/
You probably need one of these:
checkout_cart_product_add_after
checkout_cart_update_items_before
checkout_cart_update_items_after
checkout_cart_save_before
checkout_cart_save_after
checkout_cart_product_update_after
Have a look at this.
https://www.mageplaza.com/magento-2-module-development/magento-2-events.html