I'm keen to avail myself of all the best available plugins! What are the most useful or effective ones you've found so far for GIMP 3?

Mine are:

• Batcher: For automatically processing images, in batches or singly. You can add almost any action to the processing chain, including your saved adjustment presets and G'MIC-Qt commands. Epic plugin and has become indispensible to my workflow.

• Frequency Separation: Super simple, easy and smooth setting up of a frequency separation group.

• Resynthesizer: For 'texture synthesis' or 'healing'. Tip: make sure your selection does not have feathered edges when uses the Heal Selection filter. On linux is currently only available when GIMP is installed as a flatpak afaik, unless you can build from source.