These are some useful aui taglib form validator examples:
AUI Form Validators
- Validate Age
- Validate Credit Card
- Validate Date
- Validate Email
- Validate First Name
- Validate Last Name
- Validate Password
- Validate Phone Number
- Validate Price Range
- Validate Select/Combo box
- Validate Url Address
- Validate User Name
Form attributes list
You can find a useful list about the available AUI Forms atrributes here
Forms and Validation Tips
You can find more examples or tips at Liferay Official Docs about Forms and Validations.