VSTO Add-ins (edit)
https://docs.microsoft.com/en-us/visualstudio/vsto/programming-vsto-add-ins?view=vs-2017
https://docs.microsoft.com/en-us/visualstudio/vsto/architecture-of-vsto-add-ins?view=vs-2017
Developing Your First VSTO Add-Ins
https://blog.tallan.com/2018/06/26/developing-your-first-vsto-add-in/
Outlook’s slow add-ins resiliency logic and how to always enable slow add-ins
Pega for Outlook add-in and Pega for Outlook VSTO add-in comparison
Redmine Outlook Add-in
https://www.redmine.org/plugins/redmine-outlook-addin
PowerPoint Add-in for Developer
https://thecolorofcode.com/2019/01/30/howto-create-a-powerpoint-addin-in-c/
https://github.com/robibobi/powerpoint-timer
Outlook Add-in for Developer
https://www.codeproject.com/articles/93288/add-in-programming
https://www.codeproject.com/articles/155283/addon-programming-and-an-outlook-addin2
https://www.codeproject.com/Articles/31971/Understanding-SynchronizationContext-Part-I
Configuring a Web Server to Allow Excel File Creation via the Interop.Excel Namespace
AngularJS + Excel VBA as Web Server with REST
https://exceldevelopmentplatform.blogspot.com/2018/03/vba-c-excel-as-web-server-with-rest.html
New in Outlook for developers (09/18/2015)
https://docs.microsoft.com/en-us/previous-versions/office/jj228679(v=office.15)?redirectedfrom=MSDN