ZaapIT - Mass Merge, auto merge, duplicates cleanup, bulk edit, bulk update, bulk delete , mass lead convert
Duplicate Check - Start creating data happiness. Find, merge and prevent duplicate records in your Salesforce Organization.
Cloudpond - Cloudpond is an AWS S3 storage connector utility for Salesforce.
Cloudingo - Cloudingo - a cloud-based SaaS, connects to Salesforce and allows system administrators to scan their entire database for similar or duplicate records.
DupeCatcher - DupeCatcher is a provider of Salesforce data quality and cleansing software.
ImportBuddy - It gives you a very easy solution to Add/Update CSV data into any standard or custom object of Salesforce without leaving Salesforce.com