Rebellion Sourcebook: details the views of the various factions. Also lists information on the various major races. Includes tables from other traveller sources for force stregths of various worlds.
Fighting Ships of the Shattered Imperium: Worthless for ship designs. Incluudes details on force oganization for the Imperial Navy. Hotly debated organization, BTW.
Knighfall: Ruleswise, little. Excellent long-adventure, sort campaign.
Hard Times: Rules for regressing worlds due to hard times. Includes the pregravitic spacecraft rules that appeared previously in challenge. Includes Starmerc generation rules, in a 3rd style of CG rules, neither basic nor advanced, but somewhere between. Also includes adventures.
The Flaming Eye: DGP. Adventure in the Ziru Sirkaa, aboutt priacy. Excellent read.
Challenge: Several good issues, but the most important is the one which is titled "Wood, Wind, Fire and Steel" (or is it steam) which gives rules for lower technology vehicles.
Another good one is the trio of Wet navy articles, which again expand the design envelope. Both of these, however, add volume back into the equation for armor, and thus designs with these do not match up with "Stock designs".