SharePoint online List - How to find the items that a particular user have access

Hello,
To find the items a specific user has access to in a SharePoint list with unique permissions, you can follow these steps:

1. **Go to the list or library** and open it.
2. Select **Settings**, then **Library Settings** or **List Settings**.
3. On the Settings page, under **Permissions and Management**, select **Permissions for this list** or **Permissions for this document library**.
4. You will see site-level security groups. Just above, you will notice a message: "Some content on this site has different permissions from those you see here."
5. Click on **Show these items**. It will now display the lists or libraries on your site that have unique permissions.

However, please note that this method will show you all items that have unique permissions, not the specific items a particular user has access to. For that, you may need to use SharePoint administration tools or PowerShell scripts to query item-level permissions.
I hope this helps!
Best regards,
Adama