I'm not asking to make the game easier by implementing something like the fertilizer pump (very overpowered in my opinion), but some tools to alter your surroundings would be nice.
My first suggestion is the one I really want to see: drainage pump.
This would be able to dry up marshy and muddy soils, allowing you to build on them.
The Dutch have been pumping water for centuries to keep their lands dry.
(optional: advanced pump for drying up small lakes)
Second: fertilizer pump or some other implementation of making soil more fertile
My colonies rely heavy on aggriculture for food, clothes, wood and income.
It only makes sense for actual colonists that farm a lot to start making improvements to the ground for more yield/quicker growth.
Making desert soil super fertile is maybe a bit much, but making it like 60% as fertile as regular soil sounds kind of fair I guess.
Irrigation and basic forms of fertilizer have been used for thousands of years.
Anyway, maybe someone already made these mods, if so I would appreciate a link to them.
Depending on how you play there are a few mods to choose from. I like all three and take turns playing between all of them. I haven't tried Telkir Terraforming yet but I've used all of his other mods and in my eyes the are well balanced, so i foresee the Terraforming to be OP.
Telkir (T's mod Terraforming) lets you fill in ponds and lakes over time
https://ludeon.com/forums/index.php?topic=4373.0
Haplo (Miscellaneous w/o MAI+Robots) look at the objects one for a drainage pump
https://ludeon.com/forums/index.php?topic=3612.0
dismar (Vegetable Garden) with research you can reclaim land
https://ludeon.com/forums/index.php?topic=12934.0
Hope this helped, there may be more mods but these are the ones I know of if I missed anyone's sorry.
Im in the same boat as OP with current colony, some really awful marshes in my way.
A standalone would be great as these all come with a ton of other stuff and/or need a new map