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The main focusing is primarily on what they contribute on the Post-Function side of a Transition.

Workflow Enhancer for JIRA

Marketplace: https://marketplace.atlassian.com/plugins/com.tng.jira.plugins.workflowenhancer

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Several part of the Post-Functions "Create" or "Add Comment" - I never got them working

JIRA Misc Workflow Extensions

Marketplace: https://marketplace.atlassian.com/plugins/com.innovalog.jmwe.jira-misc-workflow-extensions

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Number 8 and 9 is quite existing and worth examining further.

Also, Number 19 is pretty unique - the possibility to transist linked issues.

JIRA Suite Utilities

Marketplace: https://marketplace.atlassian.com/plugins/com.googlecode.jira-suite-utilities

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One of my favorites, one of the reasons being that it is free  

JIRA Workflow Toolbox

Marketplace: https://marketplace.atlassian.com/plugins/com.fca.jira.plugins.workflowToolbox.workflow-toolbox

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One of the best on paper (I have not worked with it) - its not free, but its a afordable...

Scriptrunner

Marketplace: https://marketplace.atlassian.com/plugins/com.onresolve.jira.groovy.groovyrunner

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Several of the plugins above have better or equal as good post-functions (and sometime easier to use) than the scriptunner.

HTTP Request Workflow Function

Marketplace: https://marketplace.atlassian.com/plugins/com.hascode.jira.httprequest-workflow-function

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