Actually, the only rule included in the
Transports Attacked booklet (for tugs and LTTs) is already in the current version of the
Reference Rulebook; so the
RRB should be enough to get you up and running with the array of Main Era Alpha Octant Ship Cards currently in the game.
To clarify, the Main Era refers to the time period in the Alpha Octant running from the start of the General War through the ISC Pacification and the Andromedan Invasion; it's the same default setting as that used in
A Call to Arms: Star Fleet and
Starmada, where "pre-war" ships (like the Klingon D7) have been given various refits, and the new "war" classes (like the Klingon D5) have taken their place among the Alpha empires' battle fleets.
If you wanted to go further afield, the
RRB also incorporates the specifics needed for battles in the M81 Galaxy (such as during the Seltorian Revolt against the Tholian Will); certain Ship Cards will also include the relevant data included on them (such as on Neo-Tholian Ship Cards; which allow for the use of disruptors in the Milky Way, and particle cannons in the home galaxy).
If you want to try the Middle Years (the "TV era"; when the "pre-war" ships didn't have their refits yet, and before the "war" classes were built) you'd need the minor rule adjustments in the
Briefing #2 Rules and Scenario Pack to use the various
B2 Ship Card packs (which, like
this one, are also on e23).
Also, if you ever felt like taking a trip to the
Omega Octant (a wild and warlike segment of the
Milky Way Galaxy) the current (playtest) rules are over in the
FC Omega Playtest Rulebook, though bear in mind that setting is not formally published in
Federation Commander at this point in time.