As it might be beneficial for rats to know how to unlock systems, e.g. to perform rescues there, the relevant info from the forum-threat was condensed into a table.

Planets / Moons and regions of space without possibility to unlock yet were left out.

The info on this page comes from https://forums.frontier.co.uk/showthread.php?t=122593

 

Federation

SystemGovernmentRankBenefit
SOLFederationPetty Officer

Hand-crafted system, some good trade route destinations. 20% discount on the Eagle at Daedalus station. Two "palm tree" stations, (M.Gorbachev and Galileo).

BETA HYDRIFederationChief Petty OfficerEdmondson High Station has 10% discount on eagle. Black Mausoleum beautiful palm tree station is also present.
VEGAFederationChief Petty OfficerAccess to rare good (Vegan Slimeweed). Fort Dixon also reportedly has a palm tree station.
PLX 695FederationWarrant Officer

 

ROSS 128FederationEnsign 
EXBEURFederationLieutenant 
HORSFederationLieutenant Commander 
4 SEXTANTISFederationn/aCurrently unclear if access can be gained.
CD-44 1695Federationn/aCurrently unclear if access can be gained.
LFT 509Federationn/aCurrently unclear if access can be gained.
MINGFUFederationn/aCurrently unclear if access can be gained.
HIP 54530Federationn/aCurrently unclear if access can be gained.
Note: Overall benefits of ranking up with Federation includes access to the Federal Dropship (FDS - Midshipman), Federal Gunship (FGS - Ensign), Federal Assault Ship (FAS - Chief Petty Officer) and the Federal Corvette (Rear Admiral).

Empire

SystemGovernmentRankBenefit
ACHENAREmpireSquire 
SUMMERLANDEmpireLord 
FACECEEmpire

Earl

 
Note: No special benefits known so far for Empire systems, but community goals have been known to occur in permit-locked systems. Benefits of ranking up with Empire includes access to the Clipper (), the Cutter (), the Imperial Eagle () and the Courier ().

Alliance

SystemGovernmentRankBenefit
ALIOTHAllianceAlioth Independents

Irkutsk station - ship discounts - Orca costs 38m (20% discount), Asp costs 5.3m (20% discount). Very beautiful and clean station, palms grow around docking bays. All minor factions belong to Alliance, easy to build up your Alliance rep.

Rep Systems: 78 Ursae Majoris, Alyuto, LP 131-66, Phekda, Sobek, Doris, Ethgreze, Hera, Holiacan, Mizar, Ross 112, Tacae

Independent

SystemGovernmentRankBenefit
SHINRARTA DEZHRAIndependentElite status in Exploration, Trading or Combat10% Discount, access to rare good (Waters of Shintara), all ships and all modules available for sale.
CD-43 11917IndependentMust prestige on CQC at least once by getting to rank 50 and then resetting back to rank 1With access to Attilius Oribtal you'll be able to take advantage of a whole host of discounts, including 20% off certain ships such as the Fer-de-Lance and the Vulture, 50% off chaff and heatsink launchers, 30% off most small and medium weapons and more. Source: http://us2.campaign-archive1.com/?u=dcbf6b86b4b0c7d1c21b73b1e&id=413c006bf1
TERRA MATERIndependentBrotherhood of Terra Mater

Access to rare good (Terra Mater Blood Bores)

Rep Systems: Hecate, LHS 137, Njunmin

JOTUNIndependentDukes of Jotun

Access to rare good (Juton Mookah)

Rep Systems: Djaujang, Caleta, Blanquichu, HIP 13750

SIRIUSIndependentSirius Corp

Decent outfitting, is the location of an engineer. Permit can only be obtained from Procyon, Luyten's Star and Avik.

Rep Systems: Avik, Procyon, Luyten's Star, Te Kaha, HIP 8396, Takurua, Almagest, Robigo, and Sothis.

VAN MAANEN'S STARIndependentSublime Order of Van Maanen's StarRep Systems: Tau Ceti, YZ Ceti, Epsilon Eridani, IL Aquarii, TZ Arietis
LUYTEN 347-14IndependentLuyten 347-14 Prison ColonyRep Systems: LHS 3531, LHS449, Luyten 205-128, Stopover, Narenses, LHS 44
PEREGRINAIndependentPeregrina AristocratsRep Systems: HIP 18609, KAGUTSUCHI, HIP 19157
HODACKIndependentHodack Prison ColonyRep Systems: Amalangkan, Chuelchs, Solati, Delkar, Codorain and Dhathaarib
CROMIndependentCrom Silver BoysRep Systems: 69 G. Carinae, Herthe, Laifangyi, Bunuras, Un Naraya, Alpha Chamaelontis, LFT 568
LTT 198IndependentLTT 198 OrderRep Systems: Theta Sculptoris, Kigandan, Arngi, Tavgi
NASTRONDIndependentDefence Party of NastrondRep Systems: Wonorne Nu, Daruwutja
TILIALAIndependentConservatives of TilialaRep Systems: Varpet, Bedaho, Skardee and Akandinigua
PI MENSAEIndependentPi Mensae BrotherhoodRep Systems: Alpha Chamaelontis, Walgan, Mazahuanses
ISINORIndependentChapter of Isinor faction

"Convoy beacon" game play content. Basically there is a Type-9, escorted by two Federation security vessels (with no cargo) which holds resonating separators and a special good called "antiquities" in small and varying amounts. These special goods can be sold at any black market for roughly 90k depending on demand.

Rep Systems: Anotchadiae, Reshas, Chemaluk, LTT 5053 and Parsaka