This is a paid asset, but now you can download UI Node Connect Free.
Detail this asset from Unity Store: Original Link
UI Connect v1.0
UI Connect is an easily customizable UI framework to turn UI Objects into connectable drag/drop blocks.
Customizable UI framework with Wirable drag/drop blocks and a custom UI line renderer to create interactive interfaces as flowcharts, circuit boards, connection puzzles, node graph and others.
Add your own sprites, texts, colors, buttons and turn any UI Object (with an Image component) into a Connectable Block.
Make your Canvas part of your gameplay by adding a new interaction way for the users to manipulate and connect UI Objects with each other by a Line or SPLine.
Use the API to acess and/or set the system variables, check and analyze the connections, create logic conditions, or even expand the C# code to your needs.
Features:
Drag/Drop Blocks
Logic and visual connection
Verify crossing lines
Connection types (SPLine, ZShape, 2 points Line)
Line color and width
Canvas Render Mode: Overlay, Camera, World Space
Line Caps
Line Animation {type: Lerp, Constant Speed; number of points, points size, points color; draw type: Square, Circle, Triangle; speed}