AdaFruit, Seeed, SparkFun, DFRobot, DigiKey
Over at AdaFruit they have a breakout for the UDA1334 I2S stereo DAC. Logic levels and power can be either 3.3 or 5v and is capable of 96kHz at 24bit resolution.
Beam is an end to end pluggable LED matrix that talks I2C back to a 3.3 or 5v micro. You can connect up to 4 of them together to give you 480 LEDs. After that I figure the power demand would be too high.
If you’re looking to build a board with a USB Type-C connector, I found this chip from STMicro. It’ll manage USB Type-C power sources or devices with a programmable 600mA power switch. Essentially, if you want to power your device from USB Type-C, then get one of these.
Over at Pololu there’s a number of step up/down voltage regulators with fixed and variable voltage outputs from variable voltage inputs. They’re all essentially the same board based on the S9V11 series switching regulator, but with different components.