xna topic
FlatRedBall
Cross-platform 2D game engine focused on ultimate productivity built in .NET
Gum
Flexible layout tool for creating UI on any platform
TConvert
A combination tool for managing Terraria content resources.
Wallop
Extensible, living/animated wallpaper engine built in C# using Silk.NET's OpenGL wrapper at its core.
FNADroid
Unofficial "FNA for Android" wrapper.
XnaToFna
Relink games / tools using the XNA Framework 4.0 to use FNA instead
EvoNet
Evolution Simulation in XNA Refresh
PC-Gaming-Redists
Automated wget script to download and install all .Net/VC++ redistributables required for PC Gaming + a few other tools (like 7zip, Powershell, etc.) Scorched earth redists policy.
DevQuickie
Quick 2D game development tutorials using MonoGame.