Here my ideas, hoping to inspire you modders! :-)

CUSTOM DYE COLORS
A mod adding many new dye colors to the existing ones, inclusive own icon showing the color. Some really strong and intensive colors, some more unsaturated (misty) colors and many more mixed colors,

SOLAR & WIND ENERGY
Adding solar panels and wind turbines with their own batteries (providing energy even in the night or at windless times) to the game.

"THE FLINTSTONES" CARS
Yes, no joke - it would be cool to have these unique, food-propelled (but not visible) cars inside this dinosaur game!

HOUSE GATE
A wide door frame, one wall wide and two walls high, nicely decorated or not. Fits in open gaps in the walls. Another variety is a door frame wide like a common door opening but also two walls tall.

ECO CROP PLOT
A crop plot with a small barrel on its side that catches and stores rain water so no water access is needed. It also contains plenty worms in the soil, no additional fertilizer required.

OIL RIG & OIL TOWER
Placed offshore close to the beach and connected with ordinary water pipes to your power generator, providing a steady flow of oil. The oil drilling tower is erected on land, but works the same.

MASTS AND SAILS
A mast item that can be placed on rafts, and also be built on top of each other to get a taller height. Each mast item can hold one sail, and also functions as ladder (player can climb it to the top where there is a small platform). Sails can be of many different types: regular square or rectangle (wide or tall), Lateen sail, rig sail, lugger sail, gaffer sail, Asian sail types, Polynesian sail types and can maybe be resized. This way, each mast can hold between one or many sails. Each raft can have one mast, or several masts, centered in the middle or on the sides. painting: each mast contains several sections of two colors vertically.

SHIP'S BOAT
A small boat that can be kept on rafts, for easier exploration. Faster than the raft, but no structures allowed, but can be loaded with some transport goods.

BARGE
Wider and longer than a raft, with rounded front and back. No need for platforms, deck can be built on directly. Can carry taller structures than a raft.

FUR
A decorative item. Those wild furs can be hanged decoratively over railings or fixed on the wall. Resembles zebra or tiger and such.

ANIMAL FARM PLOTS
Similar to crop plots, but resembling rocky undergrounds, sand (forest), or water. Can be placed on top of floors. Various types, each having smaller animals of one specific type walking on it (but never leaving it). Players can walk on it, too. Animals can be used for taming, meat, or side products. Comes already with water and the food specific for that type of animal.

CARPETS ETC.
Let's beautify our homes! Think about carpets, tiles, decorative lumber, bamboo, fabrics, mosaics, etc. and all can be colored individually or kept their natural way. Place those structures on the floors.

FABRICS
Can be used to decorate windows or doors, walls or ceilings. They hang down but move slightly in the wind. Made simply of common plant fiber. Can be dyed.

COLORED SCREENS FOR LIGHTS
Made from crystal and dye, fitting around torches or electric lights. Giving a new color to the light. Great for room design.

TRANSPARENT UNDERWATER CUPOLA & CONNECTING PIPES
The small ones come with one airlock on one side, the biggest ones have an airlock on each of the four sides. They are half round, and structures can be built inside on their floors. They come with atmosphere. Require regular posts like land structures if attempted to be built on uneven seabed ground. Cupolas can be connected with air-filled pipes to each other, from airlock to airlock. Player starts with "Logistic Cupola" that, once erected during a dive on the seabed ground, has a vertical pipe to the ocean surface, where then the player can "let fall down" goods and supplies and also climb down. once down inside the Logistic Cupola where there is now a vault filled with the previously supplied goods, the player can build connection tunnels and more cupolas. The biggest ones have a diameter of 5 floors, the smallest one has a diameter of 2 floors. If the construction of posts for the other cupolas is required (uneven ground), the player has to leave through an airlock and erect the posts during a dive.

AMOR'S LOVE DART
Not sure if this can be done. A dart that when it hits makes that player or animal falling in love with you and following you wherever you go for one or two minutes. Just for fun.

BERRY SODAS & JUICES
A mechanic or electric machine that can be filled with berries of different types, and produces berry sodas (add some special ingredient for the soda effect) or berry juices. Juices and sodas have each different positive effects on the player. Can be stored in a juice or water dispenser. Some, when getting older, become to different kinds of wine, some others just spoil, and some, when spoiled, might even aid in taming!

MEAT PROCESSOR
Mechanically or electrically processes meat to burgers, "Böklunder" sausages, fillets, etc.. Each processed meat type has its own positive distinctive effect on the player.

TENT / FABRIC ROOF
Like a sun screen above the roof platform of a house, or a small one-man tent when being out in the wild, to protect from cold and rain (but not from heat). Made from plant fibers and a little bit lumber for the posts. Can be dyed. Tent can be assembled/disassembled and stored.

BUG EGGS
When found, can be used to grow useful tamed bugs and trilobites.

RADIO REMOTE CONTROL
Requires radio. Used to control some devices of your base from a distance, like lights, gates, etc..

MORE BERRIES
Several new berry types (maybe when cutting trees?) just affecting human players as they aren't used for them as animals are. Some with positive effects, some with a combination of positive and negative effects, some with negative effects. Effects: causing helpless knock-out and bad health loss but when awakening many more experience points ("Wisdom"), going berserk and uncontrolled attacking everything and everyone around, going insane and walking and running and crawling in random directions for some minutes (don't be too close to a cliff), changing gender, and so on. But here it comes: when consumed on a regular base, the bad berries start to get some amazing good effects, while the formerly good berries can suddenly have devastating bad effects! And all can be used for some very special potions on their own, or even more special potions when mixed...

ROPE
Made from plant fiber. Used to get down from steep mountains when anchored somewhere. Remains at the location and then allows even a climbing upwards at those steep areas. Doesn't last forever.

LOOK-OUT KITE
Requires ordinary plant fibers and maybe leather and a little bit of lumber to be built, and flies higher and higher but remains at the same location on the ground through a long rope (defined by the player based on how many ropes he has added. Serves as stationary look-out. Occasionally it might happen that the rope tears apart and the kit, while slowly descending towards the ground, drifts away (assumed random wind direction) for some good distance, in bad luck cases over the ocean...

SIGNAL FIRE
Requires more fuel (lumber or straw) than a normal fire, but produces a truly huge and bright fire that can be seen from very far, friend or enemy. Predecessor of the flare gun.

TOILET
Just inside the base. Collects automatically all human feces within a certain diameter around it (assumed toilet usage), and stores it forever. Player can collect it any time convenient, and uses the feces for the known applications in the game. I could also think about a smaller mobile toilet variant, that can collect only a smaller amount of human feces when the player carries it with him.

TRAP WALLS
Erected by the player on any ground, remains low on the ground until an animal is inside this wall trap, then the four walls come up and the animal cannot escape. Slow starving, easier taming or killing. One time usage only, then it must be repaired (50%) or rebuilt.

DOUBLE & TRIPLE BOW / CROSSBOW
Loads and shoots two or tree darts at a time, triple damage!

- more to come -