A list of Extracurricular activities you can do during High school!

Sports

soccer, cricket, American football, doesn't matter what sport you do! If you aren't a sports person, read ahead.

Volunteering

Community service

Volunteering at an Animal NGO

Volunteering at an orphanage

Conducting/Helping conduct events for and NGO

Working at an NGO

Independent project

Doing an in-depth project on a specific topic, maybe even earning a prize for it if entered into a competition

Writing a survey paper

Research work

Writing a research/survey paper under the guidance of your teacher/a doctor and getting it at least accepted into a physical/online journal.

Fundraisers/any activity that helps your community

Fundraisers to feed homeless children

Fundraiser to raise awareness

Fundraiser to donate to a cause

Blogging

Display your writing skills by creating a blog

YouTube channel

If you like the idea of blogging/sharing stuff online but writing isn't for you, then you could try creating a YouTube channel.

Activities at school

Debate competition

Essay competition

Math competition

[any subject] competition, and so on..