Hi there,

The most recent badges that were retired were:

• Picking Up Steam - Quickly & correctly answer 5 skill problems in a row (time limit depends on skill difficulty)
• Going Transonic - Quickly & correctly answer 10 skill problems in a row (time limit depends on skill difficulty)
• Going Supersonic - Quickly & correctly answer 20 skill problems in a row (time limit depends on skill difficulty)
• Persistence - Answer a problem correctly after having some trouble with a few problems and sticking with the skill
• Sticktoitiveness - Answer a problem correctly after having some trouble with many problems and sticking with the skill

I hope this helps! Please let me know if you have any further questions.

Again, the KA wiki has very good content related to many of the interesting stuff here on KA. Some of the best users here are writers there and so it's quite the thing you are searching for. 

I actually have the Persistence badge