Rock of Bral
It is said the Rock of Bral was one of the asteroids making up the Tears of Selûne, orbiting Toril behind it's moon, a city build upon the rememnants of a human pirate empire and before that countless, more alien, civilizations. This heritage is reflected in the meltingpot Bral now is with races from Mind Flayers to humans inhabiting the city in (relative) peace.
Above is the official topside map with completely recolored with relabeled streets. Below is a cleaned-up version of the official numbered full map, and two prettified versions of an old homebrew map of the top side and lower side of Bral.
File: 4 Maps of Bral (9.3 MB ZIP)
Bonus Link: 3d interactive top side view of Bral by u/Crow-Strict
Sources: TSR's Spelljammer: Wildspace and Duane VanderPol, but recolorized by Andrew Simone (me)
This asteroid drifts through space, the remnants of the nation of Sazaur, once led by the Hive Mother, a powerful Beholder Queen. Since her passing, the Hive drifts hoping one day to reclaim the glory they knew when their Queen once lived.
If you plan to run the adventure this is from, then you should take a look at these great DM Notes.
File: The Hive (1.2 MB JPG)
Source: TSR's SJA1: Wildspace
The Arcane Inner Flow
Wildspace, the final frontier, a place so enourmous it defies even the most detailed of maps. but a few have braved Wildspace to detail the Inner Arcane Flow.
File: Original Map (1.4 MB PDF)
File: Boozehound's Rework (2 MB JPG)
File: DevilGuy's Rework (22.2 MB ZIP, includes GIMP and PSD files)
Sources: Boozehound Blue (above, left) posted the above map, but it appears to be based off Nerik's work. DevilGuy's work (above, right) was is a modernized version of Nerik's work accomodating newer campaign settings and his Spelljamming world.
Thirteen Crystal Sphere maps that match some of the locations in the Wildspace map above.
File: 13 Crystal Sphere Maps (13.1 MB ZIP)
Three Major Crystal Spheres
High quality maps of Crystal Spheres with canonical details for three major settings: Forgotten Realms, Greyhawk, and Dragonlance. The images links were broken in the source below, so hat tip to Sesserdrix for providing copies of them.
File: 3 Crystal Sphere Setting Maps (15.2 MB ZIP)
Source: Argentmantle at The Piazza forum
The Imperial City
The Imperial City of Vodoni, the capital of a violent and bloody thirsty empire, that tries to conquer everything it encounters. They are a dangerous people who practice twisted magics to bend the will of nature to their cause, not many have lived to tell the tail of their Vodoni enforcers: a half-man, half-wolf beast-warriors.
File: The Imperial City (1.58 MB JPG)
Source: TSR's SJA4: Under the Dark Fist
A ready-made moon city of domed distracts. It was a photoshop of Sarkamand by Sapiento and Mango Moon Resource 2 by KingMango (both originals available on Deviant art).
File: Moon City (395 KB JPG)