Food:
* Packet of biscuits/cookies: A box, a tin, a pack
* Packet of pasta: A box, a bag, a pack
* Packet of seeds: A packet, a sleeve
* Packet of tea: A box, a tin, a packet
Other:
* Packet of envelopes: A pack, a set
* Packet of paper: A ream, a pack, a bundle
* Packet of cigarettes: A pack
* Packet of needles: A set, a box
* Packet of gum: A pack
* Packet of matches: A box
It's important to note:
* Sometimes, the collective noun is the same as the word "packet" itself.
* The most suitable collective noun can depend on the size and shape of the packet and the specific items it contains.
* Collective nouns can be more specific to the item, such as "a sleeve of stamps" or "a deck of cards."
Let me know if you'd like examples for specific types of items!