The Core extension allows you to add tokens that you may not see in the pre-populated list.
1. Select the appropriate Network to view.
2. When in the desired Network, click "Manage."
3. If the Network has existing tokens preloaded from Core, they will appear. Otherwise, one can add new tokens.
4. To add a custom token, select "Add custom token." Then input the custom token address.
IMPORTANT: Please double-check that the custom token address is the one you intend to add. Anyone can create a token, including copycats that impersonate popular tokens. You should always verify the token address with the project, including on their official website and other official channels.
5. Once the custom token address is added, click "Add Token."
6. A confirmation will confirm the token has been added