This post will go over how to get the list field elements in a classic form. This can be useful for minor customizations to a form, or trying to customize a Calendar (Event) item form where the JSLink option is not available.
This post will go over how to expand sub-properties of an OData REST API request without using a batch request. This will be useful in SharePoint 2013+ On-Premise environments where the batch request is not available.
This post will go over how to surface a classic SharePoint HTML/JS/CSS solution in a modern page or teams tab.