The user can absorb memories selectively or not, while removing it from the source, into their body and use it in various ways, gaining some form of advantage, either by enhancing themselves, gaining the drained power, using it as power source etc., either temporarily or permanently.
Enrico Pucci (Jojo's Bizarre Adventure part 6: Stone Ocean); via Whitesnake
Daiya Higashikata (Jojo's Bizarre Adventure part 8: JoJolion); via California King Bed
Wizards and Witches (Harry Potter); via use of a Pensieve
Brain Bugs (Starship Troopers)
Xion (Kingdom Hearts)
Raem (Final Fantasy Crystal Chronicles)
Guardian Forces (Final Fantasy VIII); via Junction
Black Shadow (F-Zero)
Users of the Shadow Clone technique (Naruto)
Nagato/Pain (Naruto); via Ningendo/Human Path
Valeriana (Enchanted Garden TV Series - Echofantasia)
Miles LeComte (Heroes)
R (Warm Bodies)
Zombies (Warm Bodies)
Bec McConn (The Demonata)
Azazel (The Mortal Instruments)
Asmodeus (The Mortal Instruments)
Ingrid (Once Upon a Time); via Magic Stones
Delsin Rowe (Infamous: Second Son)
Olivia Moore (IZombie)
Headsucker (The Powerpuff Girls)
Cyber Virus (Kaijudo Rise of the Duel Masters)
Charlotte Pudding (One Piece); via the Memo Memo no Mi
Gedächtnis Esser (Grimm)
Wolvermean (Power Rangers Super Ninja Steel)
Chaos (Sora No Otosimono)
Lester Crawley (Totally Spies); via blob-shaped creatures
Vampirella (Vampirella); via blood consumption
Wazzat (Yo-kai Watch)
Memory Extractor (Mr. Pickles - Brain Download)
Memory Stone (My Little Pony Equestria Girls)
Rock Troll Stones (Once Upon a Time)
Anyone who inherits one of the nine Titan Powers (Attack on Titan) by consuming the previous holder will gain access to all the memories of previous holders.
Majin Buu (Dragon Ball series) has access to the memories of everyone he assimilated, such as those of the Grand Supreme Kai. However, he sometimes needs external stimuli to access them.
Raem (Crystal Chronicles) is a conceptual being that feeds on and absorbs memories, completely erasing coherent thought and recollection and permanently altering the personalities of those whose memories it feeds on.
Anna Marie/Rogue (Marvel Comics) can absorb the life force and the memories of anyone through physical contact.
Blindspot (Marvel) is able to selectively absorb the memories of others
James Madrox/Multiple Man (Marvel Comics)
Predator X (Marvel Comics) can absorb memories by tasting the blood of its victims.
Robbing Leech (The Powerpuff Girls)
Olivia Moore (IZombie) is a zombie who can receive the memories and personalities of people by ingesting their brains.
Charlotte Pudding (One Piece) ate the Memo Memo no Mi and is able to extract people's memories in the form of film.
Wazzat (Yo-Kai Watch), A Yo-Kai who causes you to forget things by sitting on or biting your head, absorbing your memories
Wallflower Blush (My Little Pony Equestria Girls), absorbing Sunset Shimmer's memories of her friends by using the Memory Stone.
Lester Crawley (Totally Spies)
Zombies (Warm Bodies) by eating human brains they gain there memorise