Both this version, and the Pathfinder original, make reference to "Orc Band", "Goblin Band", and "Demon Band" random encounters (e.g., "Help the town guard root some goblins from the sewers (use the Goblin Band random encounter)". Unfortunately, no such encounters are listed.
A bigger...
Likewise, both in the original and in the 5E version, in the "Trade for It" sub-section of "Goal: Retrieve Vyswava’s Mace", it says that "The party
must face three different Demon Band encounters," but there's no such encounter listed.
But players were more likely to encounter (and much more likely to survive) his body-double, as depicted on the cover:
http://static.tvtropes.org/pmwiki/pub/images/tombofhorrors.jpg
Xykon.
Or, if he's not eligible due to not actually being in a D&D product: The fake "Acerak" from the fake tomb in Tomb of Horrors. It's probably the "lich" that the greatest number of players has fought, and almost certainly the one that the greatest number of players has defeated. It's...
Psst! You'll probably get better response if you give readers some vague idea what your game actually is. I did click through to your website to find out today, but I didn't bother to do so yesterday; and I only did so today so I could snark at you here from a more informed position. ;-)
Have you READ the PHB index? (The one that's actually in the book, not the various alternate ones people have come up with). At least 10% of the fun my players had at our 3rd 5th-Edition session was marveling at how long it took to actually find anything useful in the PHB index.
Regarding...
More relevant to Act 2, but: On the original toslayadragon.com/resources site, the link for the Photoshop version of the "Regional Map" actually contains the Holdenshire County map. There doesn't seem to be a Photoshop link for the actual "Regional Map".
5th Edition only has 4 draconic age categories. This product appears to add 6 more, matching the "missing" 3/3.5/PF ones (when combined with those already in 5E).
Lucifer himself is fighting crime on Fox. I don't think a Tiefling will dissuade anyone who would otherwise see the movie. Sure, some people will complain, but they aren't the target audie4nce.
Still typo: "It's coming in June from game designers Care Boss, Kenneth Hite, and Lisa Steele".
Should be: "It's coming in June from game designers Emily Care Boss, Kenneth Hite, and Lisa Steele".