2004 · ソースブック（プレイを拡張するルール／オプション）
Monster Geographica: Underground
This supplement compiles 200 monsters from underground environments, including 92 classic 3.0 creatures updated for 3.5 rules and material drawn from more than a dozen sources. It supports random encounters, adventure building, and campaign design with creatures organized by challenge rating, keeping monsters of the same difficulty together for quick reference. An alphabetical contents section also lists creatures by type and subtype, with entries arranged by challenge rating.
スキルベース（スキルを購入または獲得）属性／ステータス制（STR、CON、PERなど）レベル制（XPを獲得してレベルアップ）
無料・Web、Android、iOS対応
LudoyaでMonster Geographica: Undergroundを遊ぼう
ゲーム情報（人数、プレイ時間、対象年齢、クレジット）の出典：BoardGameGeek。