Improvised Sneak Attack (3.5e Feat)
From D&D Wiki
Improvised Sneak Attack [(General)]
Sometimes People Who Are Not Rouges Learn How To Surprise Enemies To Deal Extra Damage
Prerequisite: Weapon Finnesse,Weapon Focus Dagger (or dagger like object),Dex Of 18 Or Higher)
Benefit: You Gain +2d6 Sneak Attack, usable under the normal circumstasnces. In addition, if you are using a dagger or similar weapon you use d8's for your sneak attack instead of d6's. Finally, you are considered 4 levels higher for qualifying for Sneak Attack, up to your HD total.
Special: This Feat Only Works If You Are Using A Dagger/Dagger Like Object And Can Be Gained Multiple Times(but the dex required increases by 2 for every time you gain this feat)