Memory manipulation — smallville

Memory manipulation is the ability to create amnesia in others, or to freely remove or view other people's memories.

People With Memory manipulation

Kevin Grady - Kevin can remove people's memories from the past few minutes. (Blank)
Sebastian Kane - Sebastian could remove any memory he wanted. (Identity)
John Jones - John Jones can also remove specific memories. (Checkmate)
Granny Goodness - Granny is shown removing (or attempting to remove) memories from several orphans, including Haley, Tess Mercer and Clark Kent. (Abandoned)
Maxwell Lord - Maxwell can also look into people's memories. (Charade, Hostage)

The Jor-El artificial intelligence has the ability to restore and alter the memories of any person he chooses.^[1]
In Season 6, Daniel Kim and Chloe Sullivan were identified by Tobias Rice as being meteor infected, and both were abducted by Dr. Robert Bethany, subjected to Level 33.1 examinations and implanted with a tracking device. Afterwards both of them were released and had no memory of what happened, suggesting that Level 33.1 has mastered the technology to erase memories. (Freak)
In Season 7, it is revealed that Zor-El used a Crystal of El to erase his daughter Kara's memories of a visit to Earth, including his attempts to seduce his brother's wife, Lara-El. (Lara)
In Season 8, Brainiac demonstrated the ability by removing Chloe's memories one by one until she could only remember Davis Bloome. (Abyss)
A lot of technology that can manipulate memories come from Summerholt and Lex Luthor. After beginning to work with the technology and adding it to his own projects, Lex developed ways to manipulate memories through science that was shown to be used by Agent Carter to interrogate Kara Kent (Lara), and by Dr. Curtis Knox to wipe his patients’ memories away after taking away powers from meteor freaks (Curse). Summholt developed the technology with Lex advancing it further. It was also the very neurotoxin technology that Lex helped create at Summerholt that Tess Mercer used back on Lex after his revival to destroy all his previous life memories (Finale, Part 2).