2024 · ソースブック（プレイを拡張するルール／オプション）
Not of This Earth
A third-party monster manual for Old-School Essentials and other old-school fantasy role-playing games, featuring creatures from other planes of existence and distant planets. The collection includes alien parasites, extradimensional warriors, planar traders, undead explorers, man-eating fungi, strange demons, and other threats with unusual motives and abilities. These monsters introduce encounters involving possession, sorcery, body horror, interplanar travel, alien technology, and bizarre bargains. Each entry is suited for use as an enemy, faction, hazard, or other encounter in an old-school fantasy campaign.
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）クラス制（パイロット、ウィザード、サイエンティストなど）
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。