The Rebel Alliance will have 5 Tech Levels that cross 3 eras.
The Rebellion Era (2BBY - 4ABY):
This era covers the creation of the Rebel Alliance up to the destruction of the DSII. (Tech Levels: 1)
The New Republic Era (4ABY - 28ABY):
This eras covers the ongoing war with the Empire with the invasion of the Vong up until the New Republilc was reorganised into the Galactic Alliance. (Tech Levels: 2 & 3)
The Galactic Alliance Era (28ABY - 41ABY):
This era covers the latter stages of the Vong war and the subsequent Second Galactic Civil War against Darth Caedus. (Tech Levels: 4 & 5)
The Rebel Alliance Tech Level 1 has the largest number of units of any tech level. The Rebellion scrounged resources from wherever they could get them and so there are a range of units available. As the Rebellion becomes the New Republic and later the Galactic Alliance their military and navy became more and more standardised. There are a number of categories of naval units:
Starfighters: Interceptors, Space Superiority Fighters, Bomber, Transports & Gunboats
Picket Ships: Corvettes, Gunships & Frigates
Capital Ships: Carriers, Cruisers, Destroyers & Battleships
Stations: Space Stations, Battle Stations & Ship Yards
Various unit have upgrade options which are all listed below:
Rebel Tech Level 1 Space Units:
Interceptors:
- R-22 Spearhead
RZ-1 A-Wing Interceptor - T-Wing Interceptor (optional upgrade unit)
Space Superiority Fighters:
- Z-95 AF3 Headhunter
Z-95 AF4 Headhunter
Z-95 I3 Headhunter
Z-95t Headhunter - R-41 Starfighter
- T-65 X-Wing
T-65B X-Wing
T-65C A1 X-Wing
T-65C A2 X-Wing
Bombers:
- BTL-B Y-Wing
BTL-S Y-Wing
BTL-S2 Y-Wing
BTL-S3 Y-Wing
BTL-A4 Y-Wing - H-60 Tempest
B-Wing
B-Wing/E
Gunboats:
- X-4 Gunship
- YKL-37R Nova Courier
Corvettes:
- CR90 Corvette
CR90 Corellian Buccaneer or CR90 Farstar (choose one upgrade)
CR90 Assassin Class - Marauder Class Corvette
- Marauder Class Cruiser
Gunships:
- DP20 Gunship
Frigates:
- Nebulon-B Frigate
Nebulon-B2 Frigate - MC-30c Friigate
- CC-7700 Interdictor
CC-7700/E Interdictor - CC-9600 Frigate
- Assault Frigate
Assault Frigate MKI
Assault Frigate MKII
Carriers:
- Quasar Fire-class bulk cruiser
Cruisers:
- Neutron Star-class bulk cruiser
- MC40 Light Cruiser
- MC80 Liberty Type Star Cruiser
- MC80 Wingless
- MC80-A
- Liberator-class cruiser
- Dauntless-class heavy cruiser
Destroyers:
The Rebel Alliance have no Destroyers
Battleships:
- Bulwark Mark I
Bulwark Mark II
Bulwark Mark III - MC-80 Command Ship
Space Stations:
- Alliance Space Station Level 1
Battle Stations:
- XQ1 Platform
XQ2 Platform
XQ3 Platform
XQ4 Platform
XQ5 Platform
XQ6 Platform
Empress-class space station
X-7 Factory Station
Ship Yards:
- Orbital Dock
- Telgorn Corporation Repair Yard
Telgorn Corporation Service Platform
Telgorn Corporation Shipyard
How exactly do you plan to fit all of these units in the build bar?
The biggest problem modders have had with adding tons of units is the game is not designed to hold so many
You can add buttons to the build bar that allow you to split units up into groups. So you can have units split into Capital Ships, Frigates, Corvettes and Fighters for example. It's pretty handy stuff and opens up a lot of options for modding.