I have been looking for doctors, saving numbers, emails and working hours in a onlyoffice spreadsheet but its not really readable at a glance. Looked around for an address books app but neither gnome calendar nor Thunderbird meet my needs.

The features I would like in an address-book( not all of them are strictly need) are:

-custom fields. -ability to customize address fields to include stuff like landmarks, floors and district(could also do with removing stuff like Postal box or countries). -custom labels for fields like phone numbers(WhatsApp,telegram) or instant messaging(discord)

Not a priority

-add notes, maybe even add multiple notes to contact. -calendar integration, with ability to add dates to contacts that can include notes.

Did try cardbook Thunderbird add-on but it is mostly unresponsive. On gitlab, the last comits was from 4 years ago and the last released version was from 2018, dispite that, Thunderbird addon store still keeps receiving new version, even in 2026 and issues are still being opened with developer responding,even a few hours ago.

All to say, I think it went close source

Anyhow, I am not opposed proprietary apps necessary(would still pick open source if its an option) just wanted to note the add-on being close source(I think) for people in case anyone wants to know.