Get outside and go for a walk, jog or run when stress is building. Exercise has proven mental health benefits. Youtube has many in home workouts, yoga, etc.
Read or re-read a book you have at home
Watch something funny on Youtube
Listen to Music you love
Try a relaxation App to help zone out or go to sleep
Spend time with and play with pets
Put together a puzzle
Start trying to learn a new hobby or revisit one you got away from like playing an instrument, knitting, drawing, etc.
Play a board game (or video game which you likely are)
Talk with your parents and family members about how you are feeling
Just put your feet up and relax. Maybe watch a funny show or movie that totally takes your mind off your day
Write your feelings down in a paper journal, text document or journaling App.
Call or video conference with a friendly face to connect and stay in touch.
Get outside on the deck or doorstep for fresh air
Try some new arts & crafts
Reorganize your room, move things around to improve your space
Clean. It's an activity that you can kind of zone out while doing and your parents will also appreciate it!
Spend time with and play with pets
Work on school work. Without any time pressure of a fixed class time you can take your time and take breaks and come back to assignments later.
Take a nap
Have a hot drink
Ride your bike, skateboard, scooter
Color, sketch, doodle
Your idea that I never thought of! :)