Participating in academic competitions show colleges that you are willing to continue learning outside of school and genuinely desire to continue growing as a student. They help showcase your knowledge and passion for a specific subject, and will bring this energy to the colleges you apply to. Below are links to competitions you may be interested in.
There are multiple writing competitions aspiring writers can enter. Link to writing competitions for students can be found [here]
The American Mathematics Competition is one of the most pretigious of their kind, and some colleges even accept AMC scores alongside SAT and ACT scores. Link to their website can be found [here]
The Art of Problem Solving have also compiled a great list of major math competitions in the US as well as competitions held in each state. Link to their list can be found [here]
For those who want to develop a peak in science, competitions may help them showcase their skills beyond what they learn in school. Link to 12 of America’s most prestigious science competitions can be found [here]