I wasn't aware SMAA could be implemented and I've never heard of CMAA. I'll do some research on those. Every version of FXAA I've seen just looks ugly in my opinion.
As far as I know, TXAA has some very specific requirements in the graphics pipeline that other techniques don't (aside from an NVidia GPU). Plus with the licencing I doubt it would be feasible for Monogame to implement.
In Directx the Geometry shaders came in under DX10 and the Tessellator (yes the Hull and Domain shaders) was DX11, so I was thinking they might be considered separately and wanted to make sure they would be considered together here.