Twin Crowns had several expansions:
"Disaster on the Wild Boar" - A Twin Crowns Adventure - ISBN-10: 0-9712145-1-4.
32 pages - "Living Imaginations Inc." publisher.
A D20 module suitable for 2nd to 4th level characters by Celeste DeAngelis, John Faugno, and Joseph Unfried.
Much of the adventure module is centered around or on the "Wild Boar", a merchant vessel overtaken by a band of Kobolds.
"Broadsides" - Naval Adventuring in the world of the Twin Crowns = ISBN-10: 0-9712145-2-2.
128 pages - "Living Imaginations Inc." publisher, by Various Authors.
A D20 book for Naval Adventuring for the Twin Crowns setting - but suitable for any RPG.
"Pirates" - Covers the Age of Pirates in the world of the Twin Crowns.
ISBN-10: 0-9712145-6-5 112 pages "Living Imaginations Inc." publisher, by Various Authors.
Created to use in any D20 setting, but is best fitted for the Twin Crowns setting.
"Twin Crowns - And Other Lands" - Geography, Culture, and History of the Twin Crowns world.
"Living Imaginations Inc." publisher, 194 pages - ISBN-10: none given, by Various Authors.
D20 Gazetteer of the Twin Crowns World.
"Agents of Faith"- Crusaders of the Gods
ISBN-10: 0-9712145-5-7, 104 pages, "Living Imaginations Inc." publisher.
By Various Authors.
Book about the Devout followers of the Gods of the Twin Crowns world.
"Spellbound - Codex of Ritual Magic", by Various Authors.
ISBN-10: 0-9712145-4-9, by Various Authors. 128 pages.
"Living Imaginations Inc." publisher.
Ritual Magic in the Twin Crowns world.
"Streets of Silver", "Living Imaginations Inc." publisher.
A Twin Crowns Adventurer's Guide, by Various Authors.
ISBN-10: 0-9712145-3-0 312 pages - 1 map insert.
Info on the City of Parma - a Twin Crowns setting that can be used with any D20 game.