I’ve recently come across a tool for Reaper that a talented developer “Neutronic” has put out called “Quick Adder”. It allows a search bar to appear with a searchable list of plugins (fx, instruments) or other actions and will quickly add the plugin to the selected track or create a new track if required. You can mark them as favourites for quick recall etc.
It makes for such an amazingly quick workflow and with a few keystrokes you can add a plugin without needing to open the browser and scroll through the list - or you can just as easily fire a macro or other action.
Here is a video of it in action:
Would love to see something similar implemented in S1!