Weapon Finesse is used for a couple of builds:
- Many high Dexterity creatures in Monster Manuals would be given Weapon Finesse (some times as a bonus feat) to improve their attacks.
- Builds using the Shadow Blade feat with a Shadow Hand martial discipline from Tome of Battle.
- Drow Fighters get Dexterity to damage vs flat-footed targets. Take with Surprising Riposte feat to get make targets flat-footed.
- The 2nd level of Champion of Corellon Larethian from Races of the Wild grants Elegant strike which Dexterity to damage in addition to Strength for longsword, rapier, elven thinblade, elven lightblade, elven court sword, or scimitar.
- The Corsair prestige class from Dragon Magazine #321 has Roiling Sea to add Dexterity to Damage instead of Strength for light weapons.
There is a handy X stat to Y bonus list.