Websites
This is a link to simons port over of the excellent Reimers tutorials in order to preserve them they entail shaders and many things comparable to or better then the rbwhitakers tutorials.
2D Series and 3D Series 1 thru 4 … plus articles
This is his xna archive with more stuff a great resource.
This is a site that has lots of basic instructions on getting started with monogame it includes working with shaders. Though sometimes it doesn’t connect the dots as well as it could.
http://rbwhitaker.wikidot.com/xna-tutorials
http://rbwhitaker.wikidot.com/monogame-tutorials
http://rbwhitaker.wikidot.com/hlsl-tutorials
Video
If you like videos batholite did a whole video series and here is his shader video.
The monogame team vid site lots of video tutorials here.
Topics on the forum.
Most of these i put both Game1 and Effect shader code examples in them.
Post with a clip shader copy pasted at the bottom here that mimics scissors and a bit more.
Shading and blending more then one image using a pixel shader. Texture scrolling as well.
Tilemaping and shaders multiple people chime in here. I post a general example.
Links
More advanced stuff or other posts here.
Prime31’s nez shaders many examples.
Here is my own github shader examples project though its not done yet
source for Kosmonaut3d DeferredEngine
The above is the source for a topic >>Here<< on the forum that entailed more then 350+ responses. It’s all about shaders..
This is a link to a list of resources that entails all sorts of things.
https://github.com/UnterrainerInformatik/GameDevelopmentLinks
https://github.com/UnterrainerInformatik/GameDevelopmentLinks#hlsl-shaders
Gpu gems the fx files are downloadable.