You can send up to 15 collection items per day as gifts. They will be deducted from your inventory.
You can also send up to 100 free gifts, but this number also includes up to 10 complex fixers that are deducted from your inventory. So, if you start by sending 100 free gifts, you will not be able to send any complex fixers. If you start by sending 10 complex fixers, you will only be able to send 90 free gifts afterward.
At reputation level 1, you can send up to 50 free gifts. This number goes up by one every time you level up. You will reach the maximum of 100 gifts at reputation level 51.
"Thank you" gifts you send to your friends are randomly generated. They are represented by blue boxes. These gifts are sent when you press the Thank button.