I just took a look, and yeah it appears the Godot 2.1 versions of the sample projects are gone from the Asset Library. I cannot remember for sure if the Godot 2.1 sample projects were there or not, but I think they used to be in the Asset Library.
I'm guessing they removed them so it is easier for maintaining the Godot 3.0 versions of the sample projects, and to reduce confusion/duplicate entries in the Asset Library. Thankfully the sample projects can still be downloaded from the Godot demo repository on the 2.1 branch, so if anyone needs them they can still get them.