@User: Caravan was released a couple of weeks ago; see the #caravan channel for announcements (the pre-check for Caravan was a bit slower in coming). All supplies beginning with "VCC" are 1.8V, and all supplies beginning with "VDD" are 3.3V, although they can range anywhere from 1.8 to 5.5V. In addition, you can use any of the 11 straight-through analog pins for routing additional power supplies, although the three that have ESD clamps underneath that they can be connected to are the best ones to use for additional power supplies. All three of those clamps are high-voltage (3.3V) clamps, so if you want a 1.8V supply with proper low voltage (1.8V) ESD clamping, then use VCCD1 or VCCD2. Ground returns for those 1.8V supplies are VSSD1 and VSSD2, respectively.

Thank you for your suggestions!