No, Greg, I’m afraid I can’t, whether you’re asking for a list of all of the sounds that are included with the program, or of all of the types of instruments you will be able to assign to players to write for in the score.
For the former, you can check out the list of sounds included in HALion Symphonic Orchestra here:
but there is no good list of the 1400-plus sounds included with HALion Sonic SE 2.
For the latter, basically any instrument you can think of, you’ll be able to write for in Dorico. We will not have support for guitar and other kinds of tablature in the first version, but if it’s a pitched or unpitched instrument that uses a regular stave, you’ll be able to write for it.