Over time, there are a lot of extra assets that clutter up the asset folder. They can be usually moved to some other folder, say, "Third Party".
Unfortunately, that's not possible with PlayMaker itself and the net.fabrejean folder that is required for Ecosystem. Could this be changed somehow? Edit: It can be moved.* (important! Don't move in the OS/Explorer/Finder etc, but in Unity). I found out that after moving there were compiler errors, so I put everything back, and the errors persisted. But restarting fixed those. So I figured that maybe moving stuff and restarting might actually also work. That seems to be the case (yay!).
In addition, Playmaker quickly proliferates in various sub-folders (e.g. plugins). Each package, e.g. PlayMaker Utils, PlayMaker Cinemachine, will also dump themselves into the Asset folder, even though there are various PlayMaker folders already.
Most folders can be moved, , but that's not really apparent for beginners.
On a related note, the sorting in the menu in PlayMaker could also need a pass. There are "Tools" and "Addons" and Addons itself has a Tools section. It's always a bit unclear where exactly the Ecosystem was again