I tried many led apps on app world but each of them was missing something. Some where limited trail editions and some supported contacts but not applications vice versa.
But this app “Advanced Os and led” is free and has tons of features.
You can set custom led for specific
1. Contacts.
2. Applications
3. Calls
And many more
Get it from here :
https://appworld.blackberry.com/webstore/content/45506/?lang=en