In the immortal words of the great Sonic the Hedgehog: "gotta go fast!"
Joking aside, some of the coolest anime characters are also the fastest anime characters. Moving at superhuman speeds allows fast anime characters to dodge their opponents' attacks and land their own, traverse the globe in a matter of seconds, or even more unique methods like folding their bodies into a thin paperlike substance. Whether it's Goku using his Instant Transmission technique, Koro-sensei flying at Mach 20 to pick up snacks in other countries, or Saitama traveling back from the moon in the blink of an eye, these characters are impossible to keep up with.
Who is the greatest anime character with a need for speed? That's for you to decide.
Due to his legendary speed, Minato Namikaze is known as Konoha's Yellow Flash. He can move so quickly that his movements can't be detected by opponents, even those with chakra sensing abilities. Besides his exceptional speed in everyday situations, Minato also possesses a unique jutsu called the Flying Thunder God Technique, which allows him to instantly teleport to any location that he previously marked with a special chakra seal. It's hard to get faster than "instantly."
Not only is Goku able to fly around at high speeds on his Nimbus, but he can also use Instant Transmission. This is a form of teleportation that works by locking onto someone's ki signature, and instantaneously following it to wherever the user wants to go. He can also bring other people along with him so long as they're touching him. Goku learned this technique while training on Planet Yardrat, so while he's far from the only user, he's definitely one of the most noteworthy.
While there's another character whose name implies quickness, Saitama is actually the fastest person in the One-Punch Man universe. When he got launched onto the Moon, he's able to arrive back on Earth in only a few seconds. Keep in mind that Apollo 11, the fastest manned mission to the Moon, had a return trip of 2 days, 22 hours and 56 minutes. Saitama accomplished in seconds what a rocket ship took almost three days to achieve.
One of Koro-sensei's most noteworthy abilities is that he can move at Mach 20. This allows him to travel to other countries within a few minutes. For the most part, he uses this ability to pick up snacks from around the world. There's no mention as to how he's able to trick locals into thinking he's not the tentacle monster who tried to blow up the moon while he's shopping.