Salesforce AppExchange for @* Marketing Cloud Engagement * - when should you consider it based on the segmentation use case example: https://mateuszdabrowski.pl/docs/config/sfmc-config-appexchange-solutions/  

Check out: 

➡️ Expectation management for SFMC AppExchange world 

➡️ Step-by-step guide on where to find the solution for your feature request 

➡️ Out-of-the-box vs Custom vs Off-the-shelf 

➡️ SFMC Segmentation state of the game 

➡️ #SQL Query Studio 

➡️ DESelect Segment 

➡️ Activation Studio  

More to come, so keep on making your life easier ;)