PlayStation 1 Editors:
Breath of Fire 3 ROM/ISO Editor (PlayStation 1).
Download Breath of Fire 3 Editor ver 1.9 (PS1)
Also available at RHDN with a full description: Breath of Fire 3 Editor
Breath of Fire 4 ROM/ISO Editor (PlayStation 1).
Download Breath of Fire 4 Editor ver 2.1 (PS1)
Since RHDN is no longer accepting updates, you'll need to get the newest version from here.
Version 1.9a fixes a bug when editing enemy stats.
Version 2.0 adds editing for accessories.
Version 2.1 update: Added a bunch of new and improved editing (too many to list, see Readme).
Can read more about the editor here: Breath of Fire IV Editor
Road Rash Editor (PlayStation 1).
Download Road Rash Editor ver 0.6 (PS1)