Harvesting
 

Is there any type of add on that can track where harvesting nodes

Harvesting Nodes, while they tend to spawn in the same general areas, are randomly located at any given time. Therefore, this isn't something that wouldn't be currently possible.

Yep.

You could probably make overlays for the map that would show where nodes of a type tend to spawn, but only for zones with 'intelligent nodes' and even then it would only give you areas and be passive, not an active "there is node x at (loc)" kind of thing. That'd just be unbalancing.

However, you can track nodes. If you're not a tracking class, there is a tinkered item that uses charges and enables you to track nodes. If you're clever with it's use, you can use it more efficiently then just 1 charge per 1 node tracked.