this talks about drag and drop accessibility.
Drag-and-Drop: How to Design for Ease of Use
Drag-and-drop has been around since the dawn of GUIs and is familiar to most users. It is a type of direct manipulation, particularly useful for grouping, reordering, moving, or resizing objects. It works as follows: As with all direct-manipulation interactions, items of interest need to be visible on the screen - for example, icons, thumbnails, or explicit interface elements, such as column dividers in a table or spreadsheet.
use purple for drag and drop
Drag and Drop for Design Systems
You probably use drag and drop in your everyday interfaces - dropping Gmail threads into folders, moving around Trello cards, or rearranging tabs in Chrome. These interactions are a lot more complex than you think, something that I learned while designing drag and drop patterns at VMware.