Unnamed Space Idle : Just a great all around idle game that is constantly adding more content and bug fixes.
Dodeca Dragons : Recently got an update that opened up the next layer after holy octahedron so lots of new content to play through.
Clickpocalypse 2 : Truly idle game that requires a bare minimum of actual clicking or babysitting. You can certainly beat the game fairly quickly but if you are an achievement hunter or completionist then the game will take you thousands of hours.
Theory of Magic/Arcanum : The amount of character choices and the prestige layer that opens up eventually means the replay value of this game is…MASSIVE. It does require more active clicking at the beginning so it does require a time investment to get going.
Cell Idle Factory Incremental : Android game that is probably one of the most polished incremental/idle games around that will absolutely take you thousands of hours to even get close to completing what is currently there. BUT it does have the option to spend money to make some things easier or to avoid ads. The cost is a few US dollars but if you hate ads or even seeing the option to spend money then skip it.