Web Apps
These web apps live in ~/.local/share/applications. They're just .desktop text files. You can make your own or remove the default ones by cloning or deleting these files.
WhatsApp is one of the most popular messaging services in the world, and the web version is a great option for Linux.
HEY
HEY is an email and calendar service that serves as a great alternative to people tired of Gmail, Outlook, or Apple Mail. It's made by 37signals where Omakub originated.
Basecamp
Basecamp is a project management service that helps small teams move faster and make more progress. Instead of patching together a mishmash of Trello, Slack, Asana, Notion, or whatever, you can have it all in one place with Basecamp. It's made by 37signals where Omakub originated.