Mini-split AC system (multi-zoned Mitsubishi or LG).
CAT-6 wired, RJ-45 connections (two in each room).
Electrical, instant-on hot water heater (no tank).
Graywater system to save on toilet flushes.
Double-gang outlet boxes (so you can have 4 outlets, instead of 2).
Air-to-Air heat exchanger (they are called many things - it replenishes stale, indoor air with fresh outdoor air without changing the temperature too much).
Steam shower.
Wiring closet.
CAT-5/CAT-6 to outside eaves of house for CCTV streaming network cameras.
Mutli-zone sprinkler system with soil moisture monitoring.
Rain-water fed cistern (for irrigation, toilet).
Laminar flow fountain with LED color-changing lights.
Green roof (it grows plants on the roof to absorb the sun's energy and reduce rain water runoff).
Natural pool (it uses plants to filter the water, not chemicals).
A mote.
A portcullis.