Narender Singh form ForcePanda wrote a two blog series about using map collections in flows. The second blog makes good use of the new generic sObject support in flows coming in the Spring ’20 release Part 1: https://forcepanda.wordpress.com/2019/12/17/how-to-create-a-map-collection-in-flows-part-1/ Part 2: https://forcepanda.wordpress.com/2019/12/18/how-to-create-a-map-collection-in-flows-part-2flow-map-methods-spring20delight/
GORAV SETH shared a quick tip on his blog about a way to create a unique collection in flowhttps://goravseth.com/creating-a-unique-collection-in-flow
The admins at https://www.xbaf.com wrote a blog on how you can create a list button that launches a flow and pass the selected record ids to be processed by the flow using an undocumented flow variable
Narender Singh form https://forcepanda.wordpress.com posted a series of blogs on how to add validation to custom flow screen components: Part 1 https://forcepanda.wordpress.com/2019/07/09/how-to-validate-custom-flow-screen-components-in-flows-part-1/ Part 2 https://forcepanda.wordpress.com/2019/07/11/retain-input-values-while-validating-custom-flow-screen-lightning-components-part-2/ Part 3 https://forcepanda.wordpress.com/2019/07/12/adding-validation-errors-on-individual-inputs-in-custom-flow-screen-components-part-3/
Narender Singh created a flow screen component for a dependent picklist tha supports picklist value selection based on the record type. https://forcepanda.wordpress.com/2019/06/11/flow-screen-component-dependent-picklists-with-recordtype-and-multiselect-picklist-support/
Douglas Ayers and Michelle Hansen developed an Apex trigger that could know when a file was being shared to a record and then call an autolaunched flow where the business logic could be implemented declaratively.