Land investors would simply want to purchase raw land. Nothing to do with partial development, but raw land. Some purchase raw land for the harvesting of trees, while others buy land for game hunting.
If you are looking for companies or groups that would be interested in partial developed land, commercial or residential, you are not looking for land investors.
There are different stages of the development some construction or development company would like to see in the purchase these type of projects.
Some like to have the land broken down by lots and approved by the city or county. Then there are some that like the lots established as well as the approval of the infrastructure.
There are middle type investors that develop land to a certain extent and sell these to other investors that take the development to the final stages and completion. These middle developers become expert at their phase of the construction process. They also have a list of developers they normally sell to.
Most of these investors would not advertise their business as they would not want to be indulged with unwanted offers of projects, that make no sense and are no what they are seeking and wasting their time.
Very few developers would start a development and take it through to completion. Most have no idea of the various construction laws for for each state nor a relationship with the local decision makers.
In doing a project in this manner they save on legal fees, establishing a relationship with the local politicians as well as city plans and permit departments that would facilitate the development and completion of the project.
You might consider going to your local permit and planning department and obtain copies of permits approved and obtained of construction and development companies that were instrumental in building the latest large development in or around your local area. This would include large buildings, residential developments, apartments that were developed.
Once you obtain this information, you might attempt to contact them of their requirements to submit projects to them or get referrals of other developers they might know. You would want to speak to their project managers
You might attempt to Google residential, apartment or land developers, Make a decision as to if any sites that appear would fit your description of what you are seeking to sell your potential projects to.
I hope this has been of some benefit to you, good luck.
"FIGHT ON"