Never used 'em.
What exactly are factions and what functions do they have in a ttrpg setting?
So what about factions in the wilderness? How do you invent the complex web of alliances, competitions, and rivalries in a place so different from a city or village?
Factions are collectives of NPCs with a shared goal that
should reflect one or more of the Campaigns themes.First thing to do then is decide what you Campaign themes are and how you want the PCs to interact with those themes
In Lost Mines of Phandelver you get a
frontier town, ripe for the taking with Factions that include the Phandalin Council, The Lords Alliance, the Order of the Gauntlet, the Redbrand Ruffians, the Zhentarim, the Harpers, the Shrine of Tymora, Merchants (Lionshields, Barthen) and Miners the Cragmaw Goblins.
They arent just places to find quest they help develop the themes and backstory of the campaign, and become a means for the PCs to engage in the setting more fully as allies, rivals, members or enemies. Factions like the Lords Alliance and the Zhentarim tie-in to the larger world making the setting more alive
As to Wilderness Factions - you also need to decide on your themes and how the PCs interact with them. The Cragmaw goblins are an example of a Wilderness Faction - Druid Circles, Hunter-Rangers, Woodcutters, a tinkers cart? are they just random encounters or do they have a story?