The following high-level features are planned for the ASP.NET Core 2.1 release:

SignalR - Real-time web framework on ASP.NET Core (aspnet/SignalR#394)
HTTPS - On by default and easy to configure (aspnet/Home#2308)
GDPR compliance - Templates updated with new privacy features (aspnet/Security#1561, aspnet/Identity#1341)
Web API conventions - Rich Swagger support without attributes (aspnet/Mvc#6870, aspnet/Mvc#6784)
IHttpClientFactory - HttpClient as a service, handle cross-cutting concerns like caching, retry logic, timeouts and circuit breakers (aspnet/HttpClientFactory#42)
ASP.NET Core Module in-proc hosting - 6x the throughput on IIS! Better startup error handling (aspnet/AspNetCoreModule#265)
Razor pages improvements - Support for areas, ~/Pages/Shared (aspnet/Mvc#6926, aspnet/Mvc#7193)
MVC functional test fixture - Easily test your MVC apps end-to-end (aspnet/Mvc#6233)
Build-time Razor - Compile Razor pages and views as part of your build, improved startup performance (aspnet/Razor#1809)
UI as a library - Package Razor pages and views as reusable libraries (aspnet/Razor#1809)
Identity UI package and scaffolder - Add identity to any application (aspnet/Home#2311)
WebHooks - Handle WebHook notifications from ASP.NET Core apps (aspnet/WebHooks#5)