The basic resource gathering buildings have two tiers, "small" and regular. If you've unlocked those, you have unlocked them all. I don't think they have any higher tiers.
There is an Advanced Rain Collector with bigger storage and fast collection.
Most of what you unlock as the game progresses are new production buildings, and new decorations. In the upgrade tree, you will also unlock the ability to upgrade people's houses, and those have all kinds of interesting capabilities. You can think of them as mini-cornerstones because they offer similar abilities but on a smaller scale (and scaled to the number of houses you've upgraded with that ability.)
Otherwise, most skill tree upgrades just make little things cheaper and/or faster, or give you new embarkation bonuses, stuff like that.
There is an Advanced Rain Collector with bigger storage and fast collection.
Most of what you unlock as the game progresses are new production buildings, and new decorations. In the upgrade tree, you will also unlock the ability to upgrade people's houses, and those have all kinds of interesting capabilities. You can think of them as mini-cornerstones because they offer similar abilities but on a smaller scale (and scaled to the number of houses you've upgraded with that ability.)
Otherwise, most skill tree upgrades just make little things cheaper and/or faster, or give you new embarkation bonuses, stuff like that.
the horrors persist, but so do we
(aka large mozz)
(aka large mozz)