Mail, Calendar, People, Tasks: remove the Exchange Online licence and these tiles will go too.Instant messaging and web conferencing: remove the Skype for Business Online licence and this functionality will disappear (there is no associated tile).

Admin: revoke a user’s administrative rights.The following settings may help to selectively remove tiles from the Office 365 App Launcher but It’s not always straightforward – and it’s also subject to change (with a new admin center on the way): I’d argue that part of consuming a cloud service is adapting to new features and functionality as they are released but that doesn’t go down well with everyone, often leaving me trying to find ways to disable or hide parts of the service. Unfortunately, not all customers want their users to use all of the features and functionality in Office 365 and the administrative controls to manage the App Launcher for all users are limited. Users can add and remove tiles from this launcher – and administrators can provide new tiles to point to corporate resources – for example a CRM platform or the company intranet. This time last year, Office 365 gained an App Launcher as part of a new navigation experience for Office 365 on the web. Please be warned that the information here may be out of date. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time.

Office 365 launcher