This is taken from a post on Reddit from a user segagaga; all credit goes to him and the producers of mods. I felt it was a great suggestion for base mods that will not radically break game, but enhance the experience. so I decided to repost it here as well.
Here is my personal list of a set of mods and description that I have been experimenting with, and found they go particularly well together to enhance the base game experience without totally converting the game or deviating from it. All these mods are compatible with each other and each tweaks one or two things to build a nice ensemble together. Not all of them have been updated with the 1.2.5 marker, however I have had no issues running them in-game. Naturally, I’ve provided the links to the appropriate workshop pages:
Beautiful Universe v2.0 Beautiful Universe builds on its predecessor by making changes to solar system and universal backgrounds to create a more authentic space nebula backdrop a la Eve Online.
Color coded pop status icons This tiny understated mod does just one thing, it changes that orange triangle for 4 versions based on populaton status, giving you an at-a-glance indication of what the problem is.
Complete Colors This rather brilliant mod adds a full RGB color picker to the faction colors screen, giving greater color variety for your faction symbol and borders, and it lets the AI use it too. This can occasionally result in overly-bold primary colors filling space, which is why the next mod is:
Subdued Borders This mod alters Stellaris’ base border style to an opaque outer line and semi-transparent interior fill like Civilization V. This allows factions to pick bold colors without looking garish or obscuring vital in-game text. This truly complements Complete Colors and the AI makes some surprisingly great combinations.
Flags: Emblems and Backgrounds This mod complements the variety provided by Complete Colors by adding new Emblems, new Background patterns, and also adding Onyx color emblems, further enhancing faction flag variety. The AI can use them too, giving you nice surprise now and then when you encounter them in-game.
Galaxies Unlimited 1.1.0 This modifies Galaxy generation to allow for larger and more densely populated galaxies, up to a limit of 5000 stars and 99 civilizations. There are other mods that do this, but I’ve found this particular one is polished and very compatible with other mods that alter galaxy formation. It also adjusts the star dispersion along spirals, giving a more natural looking spiral galaxy. This works great with:
Galaxy Centers This mod only does two things, but it vastly improves the map. The center of the galaxy is now populated with stars, and the brightness is reduced. This is for those of you who like the idea of fighting your way across the center, rather than traveling around it.
Realistic Stars A greatly practical mod, this changes the render sizes of particular classes of stars so that they are more approximate to what their real-world scale is, so that red dwarfs are small, Type G stars are medium, and supergiant Type Bs are truly dominant. Quantum anomalies are larger. It also increases the number of red dwarfs relative to the others, to more closely match real star populations. The Galaxy Map looks much better imo. I’ve come to appreciate this mod very much.
Realistic Star Colors A mod that complements Realistic Stars that modifies star rendering by altering what appears to be a self-light, white gradient and hue/saturation. The effect is rather better on in-system views. Credit to/u/bipedalshark for pointing me to it.
Please try them out for yourselves, singly or all at once. I’d love to hear your thoughts on this combination.
Steam Stellaris Enhancement Collection thanks to Acidictadpolefor creating this
Hexlist Stellaris Enhancement Set thanks to khazarboy123 for help setting that up