As mentioned in a couple other threads, the Sine Nomine books all have useful domain tools; I've JUST discovered them and spent the day picking through An Echo Resounding.

I'm curious who uses what for their campaigns, and will share my findings here as well.  My campaign world Folia is meant to be very Sandbox, but the players have been slow to leave the starting area, and I'm overdue in defining locations in the campaign area.

I've downloaded the Free:

• Issues of The Sandbox
  
• Godbound Free Version
  
• Stars Without Number (revised) Free Version
  

Anyone that has Red Tide and can compare it with An Echo Resounding, that would be most useful - as they're both the same setting, I -assume- for my purposes I can do with one or the other.

I'm leaning towards Silent Legions for the demonic cult fuckery happening in the campaign area, based on Spinachcat and Lynn's comments on the Make Occult Horror Great Again... threads.

Wolves of God sounds like fun to run stand alone, but seems lower tech than I currently need.

So I'll post as I go, see what I come up with, and would love to hear from folks that have used these tools.

Setting Basics:

• Elf Kingdom 'nuked' itself magically via big interplanar gates.   Different cults want to break the wards in the old capital to summon their senpai of choice.  (Running modified Tiamat Module, added threats of Demon cultists)
• Land is recovering, causing a land grab - the major power to the south and the PC's home nation racing to gobble it up so they find out some people have stuck around, including R.E. Howard-esque 'sorcerer kings'.
• Dragon Pantheon are worshiped by most (adopted dieties), the folks to the south seem to be worshiping a fire cult (fake deities) leaving room for a possible GodBound/OD&D Immortals campaign spin.

So American Western, with a dash of Post Apocalypse and 70s Cult movies.

I've used a ton of stuff from Sine Nomine, even if it's just reading through adventure tags from one of the many books and having an adventure idea spark. The various books are great for a number of reasons like lists of names, quick NPC generation, or creating adventure sites. A lot of that is specific to a setting but can be adjusted to fit another with little work.

To point out a couple of books that I find particularly good, I'd put Silent Legions near the top for helping with any Cthulhu-style games. It's great for generating cults, new mythos stuff, and coming up with plots. Two books that I've found great for generating sci-fi and fantasy adventure ideas are Sixteen Stars (for Stars Without Number) and Sixteen Sorrows (for Godbound). They're both short but pack a ton of content for a GM who's tired or short on time and needs to come up with an idea for the PCs in a hurry.

An Echo, Resounding is a sourcebook for Red Tide, so the two books go together. Red Tide has all of the game and setting info (apart from the Labyrinth Lord rules) and adds quick cult creation, tables of personal and place names for the various peoples, a table of businesses and what size city they might be found in, quick npc generation, several pages of random room furnishings, a dozen or so generic maps, and the diagram dungeon method of creating quick dungeons without sweating exact dimensions (it's pretty useful). There's tables and rules for making court, borderland, city, and ruin sites; these typically consist of "tags" which are lists of options for things like enemies, friends, places, and complications at a given site so that you can flesh it out and make it suitable for PCs to have something to do.

An Echo, Resounding focuses more on the big-picture stuff like mass combat, domain management, and creating larger regions (rather than smaller sites). Given your setting, you might want to give Other Dust a look. It's one of the few SN books I don't have, but I do know it covers some post-apocalyptic material. If AER suits your purpose, though, then you should be fine giving OD a pass.

Thumbing through the books I have access to, I've got to say I respect the fact that instead of saying if you'd like to go more in-depth go buy this product, Kevin gives you everything you need in each stand-alone book.

If I wanted to run the red tide setting specifically, AER is a little light, but it's a full-featured toolbox for what I need.

I use Red Tide as the setting within which I've placed my Dwimmermount campaign with the megadungeon placed in the mountain chain that separates the civilized lands from the shou. I have An Echo Resounding, and while I use details given for the Westmark I just can't grok how to make use of the resource system. I think it's because I'm have more of a build from the bottom up mindset than a top down mindset. I wish I could switch to using a top down mindset to use An Echo Resounding more, but no such luck. I've also used the sublade class from his Codex of the Black Sun to replace the astral reavers/githyanki-types in Dwimmermount.