Before Battlefleet Gothic, Games Workshop released Space Fleet in 1991.  It came with 4 plastic ships to build, 2 Imperial and 2 Eldar.  The lid of the box also was used for rolling the dice and was divided into 9 squares and where the dice stopped would determine if the attack hit or not.
GW followed up with articles in multiple White Dwarf magazine issues covering the background of the game a great deal of additional rules and stats and information on the line of metal miniatures that were produced by Citadel.
The miniatures were quite interesting and the Imperial fleet grew quite large with many new minis but also some of the support ships were actually re-used miniatures from QT Models whose ships had been aquired by Citadel like several of the miniatures in Citadel's Space Cruisers and C43 and C44 lines.
The Eldar fleet only got 2 ships, the metal version of the Wraithship, plastic ship in the box and a smaller Shadowhunter.
The Tyranid Hive Fleet defined in White Dwarf 146 was quite extensive and did feature several ships that had been part of Citadel's Space Cruiser line in the past.


Imperial Gothic Fleet

Background The original batch of minis featured in White Dwarf 139 all fit the basic design of the Gothic Battleship that was included with the game in plastic form.  A metal version was released and had some minor differences along with smaller battleship, a cruiser, and destoyer. Design Philosophy Hull strength is average.  Screens are prevalent except for the old IRONCLAD class of Heavy Cruiser.  Mainly beam batteries with offsetting arcs and a Pulse Torpedo foreword.

 

COBRA class Destroyer Mass 22 Cost 74/57 Average Hull 6 (2/2/1/1) Thrust 6 FTL 1 Fire Control 1 PDS 1 Class 1 Beam Battery 1 Pulse Torpedo (F)
FIRESTORM class Light Cruiser Mass 50 Cost 167/142 Average Hull 15 (4/4/4/3) Thrust 6 FTL 2 Fire Controls 2 PDSs Level 1 Screens 2 Class 2 Beam Batteries (F/FP/AP, F/FS/AS) 1 Pulse Torpedo (F)
IRONCLAD class Battleship (Heavy Cruiser) Mass 80 Cost 266/250 Strong Hull 28 (7/7/7/7) Armour 8 points Thrust 3 FTL 2 Fire Controls 3 PDSs 3 Class 1 Beam Batteries 6 Class 2 Beam Batteries (3xF/FP/AP, 3xF/FS/AS) 1 Pulse Torpedo (F)
GOTHIC class Battleship Mass 110 Cost 377/388 Average Hull 33 (9/8/8/8) Thrust 4 FTL 3 Fire Controls 4 PDSs Level 2 Screens 2 Class 1 Beam Batteries 2 Class 2 Beam Batteries (F/FP/AP, F/FS/AS) 2 Class 3 Beam Batteries (F/FP/AP, F/FS/AS) 2 Pulse Torpedoes (2xF)
GOTHIC class Battleship (Modified) The plastic version of the GOTHIC Battleship that came with the original version of Space Fleet is a bit longer and has extra detail in the front neck area of the mini.  Thus it should be a modified command version of the GOTHIC Battleship Mass 124 Cost 428/458 Average Hull 36 (9/9/9/9) Thrust 4 FTL 3 Fire Controls 1 ADFC 5 PDSs Level 2 Screens 2 Class 1 Beam Batteries 3 Class 2 Beam Batteries (F/FP/AP, F/FS/AS, All Arcs) 2 Class 3 Beam Batteries (F/FP/AP, F/FS/AS) 2 Pulse Torpedoes (2xF)