Answer
Canvas firmware has enabled a feature of MicroPython that allows you to use the following command to list all available modules (that can be imported with the 'import' statement):
help("modules")
The following is one example of the list of available modules. Note not all products will have the same modules as it is dependent on the device and size of memory.
__main__
canvas
hashlib
os
_onewire
canvas_ble
io
struct
array
collections
machine
sys
binascii
erno
math
time
builtins
gc
micropython
(Plus any modules on the filesystem)
At the time of writing this FAQ the most recent Canvas FW available for a particular module may not yet have support for the help("modules") command.