Use the IHostApplicationLifetime parameter and Dependency Injection to consume a RabbitMQ on startup and send a SignalR message once a message is received.
Make use of LINQ expressions to produce a Lambda expression dynamically. Build an expression for Entity Framework with the following clauses: And, Or, Any.
See the benefits of the mediator design pattern with MediatR. Example of how to set up a request, send it through a request handler and return a response.
Using a singleton is Dependency Injection to run and store all the different types of URL's and routing those URL's to different controllers and actions in MVC.