Here are just a few suggestions (in no particular order) for customizing a card (NB No offence is intended by any omissions or other mistakes in this list. If you would like a card to celebrate - or commiserate - anything not on the list, please get in touch with as many details as possible, including 'don'ts'.):
For example, I recently made a card for an eight-year-old interested in craft work, for her birthday and Mormon Baptism combined.
And another for someone who'd passed their driving test at long last. (It featured Action Man and a re-painted Barbie Beach Buggy!)