I get asked a lot about workflows. I have yet ran across a good course. If you have let me know. So I am putting together a list of workflow resources here. I hope this helps.

Office 365

It is official that Flow is the successor to SharePoint Workflows. Note that Microsoft is saying that Flow is not the replace since it has yet to reach feature parity with SharePoint Workflows. More to come …

https://blogs.office.com/en-us/2016/10/31/sharepoint-welcomes-powerapps-and-microsoft-flow/

“Support for InfoPath 2013 and SharePoint Designer 2013 will match the support lifecycle for SharePoint Server 2016, running until 2026.”

More from the cloud engineer

PowerApps and Flow

SharePoint Examples
https://thecloudengineer.blogspot.com/2019/04/flow-and-sharepoint.html

More on PowerApps and Flow
https://thecloudengineer.blogspot.com/2018/11/powerapps-and-flow.html

Workflows

SharePoint 2016

Workflows on SharePoint 2016 (2010 2013)
https://technet.microsoft.com/en-us/library/jj219638(v=office.16).aspx

Working with Web Services in SharePoint 2013 Workflows using SharePoint Designer 2013
https://msdn.microsoft.com/en-us/library/office/dn567558.aspx

Overview of workflows included with SharePoint (2010)
https://support.office.com/en-us/article/Overview-of-workflows-included-with-SharePoint-d74fcceb-3a64-40fb-9904-cc33ca49da56

SharePoint Designer 2013 (MSDN)
https://msdn.microsoft.com/en-us/library/office/jj554671.aspx?f=255&MSPPError=-2147217396

Ninetex Workflow Upgrade 2016
http://help.nintex.com/en-US/nintex2016/current/Default.htm#NW-Upgrade/aa-top-upgradeguide.htm%3FTocPath%3DGetting%2520started%7CUpgrading%2520to%2520Nintex%2520for%2520SharePoint%25202016%7C_____0

SharePoint 2013

Quick Reference 2013 Actions and Conditions

2013 Workflow Actions
https://msdn.microsoft.com/en-us/library/office/jj164026.aspx

2013 Workflow Conditions (MSDN)
https://msdn.microsoft.com/en-us/library/office/jj822976.aspx

Missing 2010 Workflow Actions (MSDN)
https://msdn.microsoft.com/en-us/library/office/jj163929.aspx

Infamous Workflow kicking of when File Checked Out / Just been created in document library
https://www.linkedin.com/pulse/infamous-workflow-kicking-when-file-checked-out-just-been-de-roock

Visio Shapes in SharePoint Designer 2013 (MSDN)
https://msdn.microsoft.com/en-us/library/office/jj856990.aspx

Secondary Workflow (2007,2010,2013)
https://support.office.com/en-us/article/Create-a-secondary-workflow-6b77ffd5-9ad6-4c20-b5a4-d686e2deafc2

How To Design and Customize Workflows (2010,2013)
https://support.office.com/en-us/article/Introduction-to-designing-and-customizing-workflows-32c9c0bf-5e20-4f74-8b9c-d3ea79f2962b

Overview of Workflows (2010,2013)
https://support.office.com/en-us/article/Overview-of-workflows-included-with-SharePoint-d74fcceb-3a64-40fb-9904-cc33ca49da56
https://support.office.com/en-us/article/Introduction-to-workflows-15d0d459-cce8-4d8b-b34f-9ab6cda1075b

Introduction to Workflows (2007,2010,2013)
https://support.office.com/en-us/article/Introduction-to-workflows-ee1efda5-82d8-4bb3-aa6b-544a2102fcff

Create a Workflow (2007,2010,2013)
https://support.office.com/en-us/article/Create-a-workflow-f6a92a4b-c919-40d7-9728-2e79c524764c

SharePoint Designer 2010 Resources

https://support.office.com/en-gb/article/SharePoint-Designer-2010-Resources-98376b15-ab11-4ec0-a23f-c8e58c1465cf

Getting Started with SharePoint Designer 2010
https://support.office.com/en-us/article/Get-Started-with-SharePoint-Designer-2010-35A4AEAD-FA83-42A7-B0AF-5F152F06A16A

Workflow History Issues- Upgrade Issues

Myths and Truths
https://blogs.technet.microsoft.com/zsoltilles/2017/05/24/myths-and-truth-about-the-sharepoint-workflow-history-list/

Powershell fix after upgrade
https://exploresharepointfeatures.com/2014/05/06/sharepoint-missing-workflow-history-after-migrationresolved/

Legacy Updates

What's new in workflow in SharePoint Server 2013
http://technet.microsoft.com/en-us/library/jj219638.aspx

Start: Set up and configure SharePoint 2013 Workflow Manager
http://msdn.microsoft.com/en-us/library/office/jj163276(v=office.15).aspx

Setup 2013 Workflow Manager - This good article series by Spencer Harbar focuses on the deployment and configuration of a highly available, SSL, Workflow Manager Farm for use with SharePoint 2013
Workflow Manager Farms for SharePoint 2013 Part One
Workflow Manager Farms for SharePoint 2013 Part Two ...
Workflow Manager Farms for SharePoint 2013 Part Three ...
Workflow Manager Farms for SharePoint 2013 Part Four ...

Loops in SPD 2013 Workflow
http://www.nothingbutsharepoint.com/2012/10/24/create-sharepoint-2013-workflow-loop-by-using-sharepoint-2013-designer-preview-aspx-2/

Call Web Service via Workflow
http://spandps.com/2013/03/05/sharepoint-designer-2013-workflow-action-call-http-web-service/

CSOM Errors
https://blogs.technet.microsoft.com/sharepointdevelopersupport/2016/10/19/fixing-error-the-request-uses-too-many-resources-in-csom-rest-operation/?utm_source=twitterfeed&utm_medium=twitter&utm_campaign=SharePointDevNews

Troubleshooting Workflow Server and SharePoint
https://msdn.microsoft.com/en-us/library/jj193529(v=azure.10).aspx
https://msdn.microsoft.com/en-us/library/office/dn508412.aspx
http://www.harbar.net/articles/wfm2.aspx

Notes from a student …

Import the Workflow Manager SSL Services Certificate to the SharePoint Certificate Store.
Execute the following Windows PowerShell:1 $trustCert = Get-PfxCertificate "c:\wfm.cer"2 New-SPTrustedRootAuthority -Name "Workflow Manager Farm" -Certificate $trustCert
Watch out with this cmdlet. If the certificate file doesn’t exist it will still create a trust! Make sure to watch the output for any errors.
If there are some, you will need to delete the trust before running New-SPTrustedRootAuthority again after resolving the problem.

Register the Workflow Service connection with SharePoint by executing the following Windows PowerShell:1
Register-SPWorkflowService -SPSite "https://intranet.fabrikam.com" -WorkflowHostUri "https://wfm.fabrikam.com:12290"
Watch out with this cmdlet. If this command fails the Service Application Proxy will still be created but it will be effectively broken. Again monitor the output for any errors.
Clean up the connection and re-run Register-SPWorkflowService after resolving the problem.