activa 

Lightweight multi-platform ORM for mobile, desktop and servers. A data provider is required to use this library. Providers for Sqlite, SQL Server and MySql are available on Nuget.

General purpose library for expression parsing, template rendering, type conversion, configuration management, ...

Velox.DB data provider for SQL Server 2008+ for use in .NET 4.5, Xamarin.iOS and Xamarin.Android

Velox.DB data provider for MySql (Windows servers and desktops)

Velox.DB data provider for Sqlite, supporting .NET 4.5 (Windows), iOS (Xamarin), Android (Xamarin) and Windows Store Apps for Windows Phone 8.1 + Windows 8.1. To use this driver with Windows Store apps, you... More information

Lightweight ActiveRecord-inspired ORM for .NET, Windows Phone and Mono(Touch/Droid)

General purpose library for expression parsing, template rendering, type conversion, configuration management, ...