Hey there 
It’s true that fog.db doesn’t have a large impact on loading times. Packs have less of an impact than actors, items, scenes, etc., but they may still have an impact.
You may want to consider using a Shared Compendium to move packs out the world and into modules. That way, the initial load won’t take as much of a hit.
This can also be done with actors, items and scenes, especially if they can be archived or you don’t need them close at hand.
Additionally, if it’s a game that has been running a long time, you should check your messages.db file size. Especially for text based games, that can get quite large. The DF Chat Enhancements module provides an easy way to back it up.
Hope that helps! Shout if you have any trouble