Civ Resources
The "civ" community has created many resources to help players get familiar with the various plugins and mechanics. CivWiki is a huge resource for all things civ related.
The core plugins whose mechanics are shared by most "civ" servers are:
Citadel - Allows you to "reinforce" blocks and lock chests and doors.
NameLayer - Group management
Bastion - Used to secure an area
FactoryMod - FactoryMod allows for the production of items, crafting of special blocks like Bastions, and do things like compress items or printing.
JukeAlert - This plugin allows the creation of "snitches" which can report activity around them and for jukebox snitches, log that information as well.
RealisticBiomes - Realistic Biomes is a plugin that gives each biome their own crops and trees with much longer grow times.