Tannhäuser and Lohengrin are complete now. Together there are more than 300 recordings listed. Interestingly Der fliegende Holländer seems to be more popular than Tannhäuser at least if we look at the number of recordings (probably a very good indicator). I guess the reason is that the flying dutchman is easier to stage and cast which makes it especially for smaller opera houses more attractive.
Next will be Tristan, first the video and then the audio recordings.
And as always, if you own or aware of any recordings that are not listed, please contact me.