The more interesting games periodically introduce new mechanics or completely rebalance old ones, rather than just repeating the old mechanics with ever more powerful buildings and upgrades. Very recently,
Succubox, though it's relatively short, plus the older
Mine Defense,
Kittens Game, and
Sandcastle Builder (
Classic Layout, less confusing at first, but lacking the customizability that starts to become convenient a few weeks in).
The thing is, most of these games are best enjoyed as a separate browser window off to the side, especially on a second monitor, while you do something else. Also, many of the better ones quickly move past clicking for resources as a meaningful mechanic, and instead into some form of managing resource flows and optimizing purchase sequences for ROI. Also, discovering new mechanics as you progress is one of the key reasons driving playtime. At least for the more popular free browser-based ones, where they are competing with the entire rest of the internet for player attention, rather than filling dead time as a phone app on the daily commute.