Your wishes for a development plan

Semi-detached and terraced houses only from the same construction company

That seems to me to be practically prescribing something unnecessary, insofar as, in my conviction, reality reliably punishes it if you act otherwise ;-)
Joking aside: legally clean, I consider this (only?) feasible via the approach that for E/D plots, the permission possibility for D development is linked to the condition that both building applications must be submitted by a common planner.

if you were allowed to participate in a development plan for a new residential area, with single-family houses, semi-detached houses, terraced houses, and multi-family houses.

but I have no influence on that, if the municipality sells to private individuals, the builders will have to work together...

It just occurred to me what your intention in asking is. At first, I thought of a hypothetical chat or preference discussion in the style of the hype thread. Now it dawns on me that you want to survey us as a "base" representing the population of your municipality about what you, as a municipal councilor, should strive for. Here, it seems to me (in the form of the naive assumption that development plans originate from a blank sheet) that there is a misunderstanding of municipal political processes. However, this usually does not work that way – you can educate yourself with "explanations" for development plan formulations, as are offered in abundance on the online portals of town halls. Obtain such concerning recent previous establishment procedures from your area, then you can develop a feel for the manner of creation, i.e., read retrospectively where one could already hear the nightingale singing. Even in the construction of such documents, you can trace "historically" how the plans come into being. Typically, at the beginning stand the coming together of two elements, namely on the one hand a need and on the other hand a suitable area for corresponding replanning. That means the municipality establishes a need for action and demand. Sometimes the chicken comes first, and sometimes the egg. That means in one case there are first those wishing to settle, and in the other case the area. Prospective settlers can be both long-time residents who have reached family-forming age who currently rent or for whom the parents' house is too small. Or but newcomers from the region whom the municipality wants to recruit to take up residence with it rather than in the neighboring town. The area can, for example, consist of fields where farmers give up their farms; or also from an industrial brownfield to be revived for residential building purposes. This exemplary matrix of two times two planning occasions may show you four typical cases of development plans. Furthermore, it is always worthwhile taking a look at recent development plans (or amendments to older ones) from the area: from these you can both deduce what particular demand is seen and examples of misdevelopments that are to be avoided. Both can be read out with some practice from the explanations. Real surprises in "new" development plans thus actually only exist for municipal parliament beginners. By the way: spatial planning / development / construction planning are classic fields where men of at least middle age are convinced of their innate intuition. Women who do not want to end up at the kids' table here are well advised to make each other fit and competent "girls only" and form inter-factional alliances. Municipal politics is – if one is not vigilant – one of the last reserves for grill-master cartels ;-)

Encouraged by hanse987, I would like to return to my earlier wish that the municipality or a municipality-affiliated institution/consulting company takes on the consultation of builders regarding construction possibilities on a specific plot of land for a fee. Or (VHS_?) offers courses regarding the buildability of plots. In my opinion, a win-win situation, because the building authorities do not have extra work due to rejections, and the builders already know before planning with the architect what is possible and what is not.

Here in the region, there is a community that enforces very restrictive development plans: facing brickwork, prohibition of shiny roofs, only gable and half-hipped roofs, defined color schemes for walls, bricks, and wood, maximum building and eaves height, single-story buildings, plant lists, prohibition of rock gardens, etc. The result is harmonious new development areas that exhibit a uniform village character but still obviously leave room for individual design. I like it and therefore use it as my guideline for development plans.

Only the single-story requirement would I want to remove, as this (at least in Lower Saxony) has massive effects and the external form can be sufficiently defined by the roof shape in connection with the ridge and eaves heights.

Additionally, it would be nice if street layouts, in connection with building boundaries and possibly building lines, were planned so that everyone has as unobstructed a view as possible. For example, my parents were lucky with this when they built.

I find it nice when development plans are oriented towards the traditional regional building culture and do not allow complete arbitrariness. There are enough building areas here with few regulations and ugly results. Honestly, I do not want pink plaster, blue roofs, or castle turrets on the 150 m2 single-family house in my neighborhood just because someone wants to go wild. The individual design freedom should certainly be limited in the interest of the general public – after all, all neighbors have to endure the result every day.

I tend not to install gas, but I think we won't get away with it.

Until now, I thought gas is hardly ever installed anymore? My husband and I will have gas available in our building area (about 17 years old) and will also use it, as required, together with solar thermal energy.

The individual scope for design should definitely be limited in the interest of the general public - after all, all neighbors have to endure the result every day.

It all has its pros and cons. That shows that different free building regulations do make sense. If there were a "wild" and a "regulated" area in one place, I would always prefer the "wild" and you probably the "regulated." If the "regulated" one is in the context of an old town or a grown village, I think that's good. If it leads to a cluster of modern city villas and block buildings falsely called "Bauhaus style," which will be considered just as ugly in 20 years as the concrete buildings from the 70s are today, I would find that creepy. : What is already there in the area in question? What is the location like (inner, outer, mixed-use / adjacent to commercial, "Neue Heimat" next door...)? Which people do you want to attract and keep in this place?

Of course, that is still no reason to let the house be designed according to the neighbors' taste.

Above all, you have many neighbors with different tastes

Semi-detached and terraced houses only from the same construction company ;)

Why?