From the Federal Reserve in St. Louis (FRED)
This turned out trickier than expected. But I think this is pretty useful. It's the real rate for Aaa corporate bonds.https://t.co/W8b464zPfJ
— Kilian 🌍🏕☮ 🍞 (@kilianjay1) September 11, 2022
All other time series I found were either not continuous or low frequency.