The Dynamic Gaming System (DGS) uses a single d20 for all its rolls, including all Skill, resistance, and combat checks.
All basic mechanics use the Attribute + Skill + 1d20 roll mechanic. However, combat attributes (bonuses to Strike, Parry, Dodge, etc.) are garnered from their Attributes and their Combat skills.
The system is dynamic because Skills are not tied to specific Attributes. For example, [AGY (Agility) + Crafts] would be used to make a wood carving. However, inspecting the integrity of an item would require [INS (Insight) + Crafts] and creating blue- prints would require [IQ (Intelligence) + Crafts].
DGS is the house system of Third Eye Games and is used in several of the company's products, including Apocalypse Prevention, Inc., Wu Xing: The Ninja Crusade, and Part-Time Gods (1e). It is also available to third-party publishers under a free license.