A card is lovely; a card plus something tangible is unforgettable. Here are three easy ways.
1. Flowers on the same day
Order a bouquet for delivery on the day the card arrives. The organiser page suggests partners.

2. A printed photo book
Put the best photos and messages in a printed book. Photo-book services can do this from the photos you collected.
3. A small gift from the team
Agree on a budget in the team chat and pick one gift. A mug with the team photo is a classic.

Keep it simple
Do not turn it into a project. One card, one extra, delivered on the day is plenty.
