The easiest do-it-yourself approach that comes to mind is to use a shared resource. I use Google Contacts to manage a single address book that accessible to my PCs, tablet and phone. Android devices work natively with this, and Thunderbird will need an add-on such as gContactSync. If you are reluctant to use Google, you may find that your ISP or email provider has something similar, though it may not be as straightforward to sync with Thunderbird. Here's an example using CardDav: https://help.hover.com/hc/en-us/articles/217282057-CalDAV-and-CardDAV-Synchronization-for-Thunderbird DavMail is another possibility. A more formal way to do this would be to host a communal address book and share it to Thunderbird users via LDAP. But you will need a server, and competent IT folk to configure it. This is how it's done in my place of work.