A recent pdf bundle in my cabinet of holding has been these joys, I got the current Warlock book and loved it. Its aesthetics are like mine early 80s up punk fantasy. The basic book i had already and was curious about more so gobbled up this bundle. Warlock is very well-supported and very collectable. You could use it with Midderlands fine too. My own work would work most of the time with this. Its a non-dnd system perhaps like a cross between fighting fantasy and Warhammer frpg 1st ed (i don't know recent eds).
A whole city with districts and stuff to take place. Grimy history, supernatural happenings, taverns, nobility, district encounters, laws, cults, shops, markets and a nice job table. Church, weather, some new spells and more. It's not too detailed or intimidating and a quick read and is good for a few adventures or a base city. So even a dnd reader could use lots of this if your not a slave to statblocks. Its an above-average fantasy city and more usable than most. Its easy to get your head around without super detailed floorplans
A book on the lands, the king, the Traitor (a feature of the setting), Has a nice evocative map and locations you could steal or be inspired by. Lots of adventure opportunities and easy to use and apply. There is also a detailed mapped city which would work well with Rebek. There are lots of evil-doers and factions to use. New classes for characters and great miserable backstories (also usable for other games). I love the mudlark trade with a table of your best find "nothing but despair"
Marine adventures for Warlock. Lots of new occupations and advanced careers, then lots of tables for marine adventures. Lotts of plot generation for sandbox play and ad-libbing tools. A bunch of criminal generation tables. It has a system for referees to generate a world to explore with players or generate on the fly as you go. The section on ships includes 7 famous ships which is nice. Magic items and many detailed marine races and monsters.
Warlock! Compendium 3
No idea what is in the first two. Possibly bundled into other books? This has lots of fun tables in the first l section and rules for alternate play styles which are of interest to gaming in general.
A sf system based on warlock. Lots of careers and if you wanna be an alien, just take an ability and skin your species as you please or just be human or humanlike. I like it doesn't matter and the default setting is huge. Has colourful criticals, a section on tech, and every party joint owns a ship. A warp magic and mutation system and a faction of armoured fascists are a kind of 40k hat tip. A section of the setting is the Chous and various factions and rumours about them. I love the use of tables to build settings and paint a picture. There are lots of monsters and species and better word-building than many bulky books. The rest of the book id game master section. Punches well beyond its word count and very usable.
A system sourcebook and once again built from tables as lists of facts and rumours. Has notes on setting factions and various occupied worlds. The second section is several family-hefty adventures.
A book of villains, species and organisations. Also a prison complex.
A book of careers, weapons and faction lore for the armoured gun-loving millitary faction. Discusses running millitary campaigns and has a mission table and an adventure.
Describes a cluster and has 3 adventures