These are all that come to my mind right now. Do you know of any others? 2x2z5o

Zettai Karen Children (psychic)

Alive: Saishuu Shinkateki Shounen
But it's more like superpowered teenage than children.
I think there are more in the teenage category if you're okay with it.

Arma in Line Webtoon if you're into webtoon.

Just binge read unordinary. It’s great.

akira

Spy x Family

Psyren has this, but a bit later on

Be careful of your thoughts, for they will become words.

Be careful of your words, for they will become actions.

Be careful of your actions, for they will become habits.

Be careful of your habits, for they will become character.

Be careful of your character, for it will become your destiny.

Gakuen Alice - About a school for children with special abilities.

Hunter x Hunter - Gon and Killua are the MCs. They're both extremely strong and later on use 'Nen' which is a sort of psychic power that enhances their fighting abilities.

Black Cat - Focuses on a trio of bounty hunters, Sven, Train, and Eve. Eve is ~11 years old. Her superpower is that she was made with nanotechnology and so can manipulate her body's structure according to her imagination.

Bleach - Not MC, but one of the Shinigami (one of the characters who fight the series' monsters) is a child.

Card Captor Sakura - Most of the MCs are children with Psychic/Spiritual powers.

Shin sekai yori - Darker than the other series on this list. Part of the story focuses on the MCs when they were children, then it timeskips to them as teenagers.

Little Witch Academia