So of course I will start with the Caskey Memorial carved by my 2x great-grandfather, William Busby.
Of course a headstone may also be a memorial. If someone is mentioned on a headstone it does not necessarily mean that their mortal remains are buried within reach of the headstone.
Another form of memorial is the funeral or bereavement card as shown here for Alice Annie Rollason.
These cards can be very ornate.
The photo below is also a memorial. The two family members who had died prior to the photo being taken were added, fairly obviously.
Or this medallion celebrating my having given 100 blood donations.
It may be a book plate saying your ancestor had received it for perfect attendance at school or church, the key given for a 21st birthday, the first shoes worn by your baby, the inscription on the flyleaf of the Bible given for a First Communion.
We should look for memorials of all types among our possessions as these can give clues which will tell us more about our ancestors and bring them to life and may even break down a brick wall in our research.
What unusual memorials have you found in your family research?