The Battle Brothers community spans a good number of forums on the internet and it is nice to have the links all in one place to facilitate searching for information. Listed below are official forums/threads with substantial activity and various popular guides/playing aids.
Links to forums/threads/general discussion
Text guides
Overhype BB forums
Steam forums
GoG forums - not much activity
Reddit forums
RPG Codex
Something Awful
Quarter to Three
Tieba.Baidu - forum in Mandarin
Overhype Twitter
Active online chat groups
“The Fine Few” on official forums discord
Reddit discord
Links to external guides
Text guides
In-Depth Perks Guide (2020 - Blazing Deserts Updated) by turtle225 and Abel // initial posting in 2020, is currently and regularly updated (2021)
Hieronymous Alloy's Beginners guide // (2017)
Kyoko Kirigiri's General guide // (2017)
Fritz's guide on Builds, Perks, Gear, Formations // (2017)
Calmnesss13 perk discussion // (2017/2018)
Dialetheia's discussion thread // (2017/2018)
Yueguang11's enemy stats (hp, armor, estimated fatigue and approximate initiative) (in Mandarin)
Video guides
Overhype youtube channel // Tutorials were updated for Blazing Deserts DLC (2020)
Filthy Robot's "Guides, Tips, and Tricks" video playlist general introduction for new players and comprehensive perk discussion (2017), guides for Warriors of the North (2019) and Blazing Deserts (2020) DLCs
Eyestabber's early game and early mid game guides // pre-DLCs videos (2017)
Links to playing aids
Map seeds
General map seed collection
Abel's map seed reviews
Savedgames editor
Perk calculator
EveryCrime's "Battle Brothers Perk Calculator"
Unislash's "Battle Brothers Planner" (contains links to other useful resources)
Build planner
Unislash's "Battle Brothers Planner" (contains links to other useful resources)