1)   JavaScript Form Validator 3.1.0
Save yourself from repetitive coding of form validations for your web forms. Here is a simple, easy to use client side JavaScript form validation script. Using this code, you can quickly add form validations to your form.

 2)   Simfatic Forms 2.1
It is quick and easy to create, install and maintain full-featured forms using Simfatic Forms. No programming required. Simfatic Forms can read the forms from your existing web pages and add input validations or form-mail support.

 3)   SharePoint Form Validation 1.5.107.0
Do form validation when you create or edit a list item in a form; Provide standard validation methods like Require, Compare, Regular Expression etc