Special price when buy more than # items | crossale or upsale in cart | gift car

Hi how are you?
Three ideas for features

Special price or discount when the user buys more than # items.
For example: Discount or special price for the purchase of 5 books (not necessarily 5 of the same title)

For the second
If you buy an agenda, offer a related product (example a pen) in the shopping cart.

Third:
With the gift card, user A can buy user B a shirt as a gift. User B can pick up a shirt of their choice in the store

Dear Miguel,

Thank you for suggesting the features here. I will check more these features and if they are usful, I will find a way to implement them.

Sincerely, Giang