True20: Eberron

from the Introduction:
The goal of the rules presented in this document is to make it easier to play in the D&D Eberron setting (by Wizards of the Coast) using Green Ronin’s True20 rules. Although there are similar rule conversions (such as the True20 wiki, and many True20 forum posts) those either introduced new rule elements, or did not use the additional feats and powers introduced in the more recent handbooks. The overriding principle used here is to use the existing rule elements as much as possible (such as feats, supernatural philosophies etc), introducing new mechanics only when absolutely necessary.

Please note that although these rules were developed with the Eberron setting in mind, many of them could be used in any D&D setting.