Because it will help me in filling out details in terms of lairs, details and other setting details, I'm pulling together a small list of encounter types that would be common to the Egyptian Great Plains setting. As I'm mentioned before, the common animal encounters will primarily come from Pleistocene animals that once roamed the region. That's what formed the basis of the Common Animal table below. I've also looked at animals common to the Great Plains today, to fill in a few niches that may have been left open. In some cases, I've substituted fantasy equivalents for certain creatures, just to keep the fantasy feel of the setting alive. Finally, in one case, I've replaced the common American bison (the buffalo, as we grew up calling it here) with a creature from Dougal Dixon's The New Dinosaurs: An Alternative Evolution, specifically the Monocorn (although I use the name "bovalo" to refer to the creature as a reminder of the niche it fills in the setting.) The resulting Common Animals table follows:
Table: Common Animal Encounters
|2||Smilodon (Sabre-toothed Tiger)|
|3||Mastodon (Wooly Mammoth)|
|4||Dire Bear (Grizzly Bear)|
|5||Snake, Poisonous (50%)/Constrictor (50%)|
|6||Osquip Swarm (day)/Bat Swarm (night)|
|11||Glyptodon (Dire Armadillo)|
|12||Dire Lizard (50%)/Dire Crocodile (50%)|
In regards to more supernatural encounters, I dug through a few websites on both Native American and Egyptian mythology (and maybe one or two borrowed from Persian mythology, just for fun), and came up with the following list of supernatural creatures. As the setting develops, this list may change, of course, but this should do for starters.
Table: Supernatural Creature Encounters
|2||Phoenix (50%)/Thunderbird (50%)|
My third list of possibilities includes the humanoids that the player-characters are likely to encounter over the course of the campaign. These are the most common encounters, of course, and are inspired by a variety of influences. Some of the races are chosen because of their resemblance to Egyptian god images, while others are selected because they help define the type of roles that PCs are likely to find themselves in or interacting with. Given that horses pretty much came to North America with the post-Columbian European explorers, I've elected to let my nomadic tribesmen in this example ride Dire Wolves, as they are the most mount-like of the Common Animals. Thus, I call them Wolfriders. The tribesmen that dwell in villages and raise crops are called Plainsmen. I've also elected to call my pseudo-Egyptian culture the Badari Dynasty, based on the Cultures of the World Within post I made last October. At any rate, here's the basic list I came up with (and I am open to suggestions, particularly here):
Table: Common Humanoid Encounters
|2||Human Cultists (Various)|
|3||Human Slaves/Refugees (Badari)|
|4||Human Slavers/Raiders (Badari)|
|5||Human Merchant Caravan (Badari)|
|6||Human Patrol (Badari)|
|7||Human Nomads (Wolfriders)|
|8||Human Hunting/War Party (Plainsmen)|
|10||Vulturan Slavers (50%)/Mercenaries (50%)|
|11||Non-Human Mercenaries, Other|
|12||Non-Human Slaves/Refugees, Other|
I would likely modify the above list to better suit the racial selections of the player-characters, once the campaign got under way. However, for the purposes of helping to generate background details, it helps to paint the right kind of picture for this particular setting.
It is important to note that encounter tables are not mandatory. These simply capture some of my thought process on figuring out what kinds of creatures and scenarios I'd envision for this campaign setting. Since I'm already doing the work of making these lists, I figured I wouldn't waste that effort and so created the random encounter tables along the way. (Otherwise, I might end up having to do the work twice, should I decide that I need encounter tables again at some later date.) For a more generic fantasy campaign setting, you could very easily just use pre-existing random encounter tables, or just put the Monster Manual on the table as the monster resource for your sandbox setting as you move through the remainder of the creative process.
At some point, I will likely need to create stats for some of the creatures listed above (such as the bovalo, the jackalope, the wendigo and so on). Alternately, I may just take the stats of existing monsters and simply "reskin" them descriptively to meet my needs. I'll burn that bridge later, as time allows. As it stands, I probably spent an hour doing research on Wikipedia and Google, and slapping the above together. It probably took me longer to organize and write this post, with interruptions and all, than it did to research what I wanted to include in the Egyptian Great Plains campaign.
Hope This Helps,