Kensei (Bleach) can punch at extremely high speed.
Yoruichi Shihoin (Bleach) can unleashed a barrage of ultra-high-speed punches to overpower Aizen.
The Flash (DC Comics) demonstrates.
Bart Allen/Kid Flash (DC Comics)
Agatsuma Zenitsu (Demon Slayer: Kimetsu no Yaiba)
Jotaro Kujo's Star Platinum (JoJo's Bizarre Adventure)
Jean Pierre Polnareff's Stand, Silver Chariot (JoJo's Bizarre Adventure Part III: Stardust Crusaders) is a incredibly agile Stand...
...attacking enemies with barrages of sword thrusts within seconds.
Bellamy (One Piece) using his Bane Bane no Mi powers to boost his punching strength with the momentum.
The Jet Dials that Gedatsu (One Piece) has attached to his elbows allow him to strike his enemies at blurring speeds. The only downside is the impact creates holes in his clothing.
Monkey D. Luffy's (One Piece) Gear Second technique involves him increasing the flow of blood in his body. By doing so he can then use the Rokushiki/Six Powers technique, Soru/Shave and strike his opponents at super sonic speeds.
Brook (One Piece) using his signature speed strike technique Hanuata Sancho: Yahazu Giri.
Kizaru (One Piece) using his Pika Pika no Mi to increase the speed of his kick to build relativistic mass.
Shiliew's (One Piece) tremendous speed allows him to cut down several people at once in a split second.
...he is able to slice his opponents at an incredibly high speed.
Tohka Todo's (Rakudai Kishi no Cavalry) nigh-invincible battōjutsu Raikiri infused with lightning, grants her strike speed which transcends the speed of sound, releasing blinding light and huge amount of heat in the process.
Sonic the Hedgehog (Sonic the Hedgehog), using the momentum of his speed, Sonic can land devastating blows to solid steel and other durable forms of matter.
Shadow the Hedgehog (Sonic the Hedgehog), can use his incredible speed to boost his strikes to devastating levels, in the same manner as his rival Sonic.