e.g.
Framework - Which .NET framework do you use (Core/LTS)? Do you use MVC, Razor Pages, Web API and Blazor (Server or WebAssembly) or Web API and an alternative JavaScript/TypeScript based frmaework?. Do you use JSON/XML/SOAP or gRPC? How do you serialize your JSON (NewtonSoft.JSON or System.Text.JSON)?
Database - Do you use Dapper, Entity Framework or just utilize a SQLConnection object manually (And then do you use System.Data.SqlClient or Microsoft.Data.SqlClient)? Which database driver do you you use?
Authentication - Do you implement this manually? Do you use something like Identity Framework? Do you use a third party provider like Azure AD(B2C), Auth0 etc. etc.? Do you use header based authentication, JWT's etc. etc?
Jobs - Do you create a separate service project or Windows Service? Do you use HangFire or Quartz?
Email delivery - How do you render your templates? Do you send via SMTP manually or do you use a third party API like Mailgun/Sendgrid etc. etc.
Folder structure - completely up to you, no real standards there.
Testing - Do you use XUnit, NUnit, MSTest, SpecFlow?