"Originally, I was thinking about blocking users from closing their overgrown tabs until they slash all plants, but I thought it would be too annoying... "
I would ask that you please add this as an option :), might actually use it for that feature alone because I do accidentally close old tabs by accident without noticing that was meaning to keep open.
Classic joke at university was to sprinkle cress seeds on the carpet of someone's room and water it with a fine mist from a plant sprayer. In the morning the inhabitant would wake up to a neat lawn that had appeared overnight by magic.
These useless programs are like what you used to see back in win98 or winxp with dancing monkey or scoopydoo walking all over your desktop windows, which I think later turned to human dancers before being used to distribute all sort of viruses.
To put it another way, it helps me recognize which tabs I am using. And which I am saving for later without having to evaluate the content of the tab.
One tweak… the coverage percentage can it be adjustable? Max = 100% looses all information about the pages contents, except the title.
Also also… if the images can be made translucent… you can make old timey effects like yellowing and decay.
I have a ton of these tabs. I don't consider them "neglected" though.
Some things take years to come to fruition. You can't just go buy them at home despot.
Maybe younger people don't yet have an appreciation for things that assume an air of legacy and heritage after many years of "just sitting there".
When finally re-visited, they have a meaning that can only accumulate with the passage of significant time...