The user can implant memories into the minds of others, which can either be the memories of others, or false memories manufactured by the user. They can completely re-write a person's memories to change their personalities, knowledge, self-identifications, etc.
Doraemon (Doraemon) using the "Memory Disk" to extract Suneo's memory of Nobita wetting his pants, and then implanting a false memory back into him to make him inadvertently telling Shizuka that he wet his own pants from over-excitement, in which he could not stop himself from saying it until it he realized too late he humiliated himself.
Blindspot (Marvel) is able to selectively absorb the memories of others, store them within her own mind, and transfer them to others, even if they do not belong to the person or people she is giving them to
Neuralyzer (MIB); before or after use, one can supplement new memories to those affected
Jack Force (Blue Bloods Series) was able to implant a memory of a past life of him and Allegra Van Alen on her daughter.
Kessler (Infamous) can implant his memories into the minds of others, though he is only shown doing this to his past self, Cole McGrath.
Charlotte Pudding (One Piece) ate the Memo Memo no Mi, giving her the power give someone fake memories.
Nea D.Campbell (D.Gray-man) was killed by the Earl and devoured him. After 20 years he was reincarnated within Allen Walker body and implanted all of his past life memories as a host in Allen's body when he was alive.
Eidolon (Vampirella) is a mirror capable of altering memories that Lilith used to manipulate Vampirella by erasing certain memories and implanting false ones in her mind, such as...
...making her believe she was an alien with abilities identical to vampires from human mythology instead of an actual vampire,...
...that she was given birth as a result of Lilith pouring her blood into the ground of Drakulon, a location in hell, rather than being the daughter of Lilith and Cain,...
...and that Lilith had raised her to be good in order to repent for her sins when in reality she was using her to eliminate the entire vampire species because their continued existence was making her weaker.