A keepsake is an object that has sentimental value, so a keepsake in a dream can be a way for your dreaming mind to remind you of all the good that you have accomplished and all the happiness that you have given others in the past, and to make you aware of all the good that you are capable of doing in the future.
The nature of the keepsake can be significant. Does it evoke memories of a particular place or time?
Dreaming that someone gives you a keepsake can mean that you desire love and respect.
If you dream that you are giving away a keepsake, you could be trying to repress memories that are upsetting to you.
Losing a keepsake in a dream can mean that you are starting to mistrust a memory, or that you feel that you have been deceived by someone close.