"mainly include" is correct and usable in written English.
You can use it when referring to a list of items that comprise something. For example: "This dish mainly includes carrots, potatoes, and onions."
Then, the materials mainly include US and European case law.
These nanoparticles mainly include CuZr2, Ni2Zr3, and NiZr2, etc.
The remediation mechanisms mainly include liming, precipitation, and sorption effects.
Algae functioning as water indicators mainly include Synedra ulna (Nitzsch).
Self-healing products mainly include C S H and CaCO3.
This will mainly include literary characters that we look at throughout the year.
Those incentives mainly include paying high interest rates to banks, to keep them happy and profitable.
Chromosome classification is performed by identifying the morphological features which mainly include the centromere location.
Subsalt structures mainly include imbricated thrust belts, duplex structures, fault-related folds and pop-up structures.
Test results show that the effects of inner water mainly include "distributing loadings" and "ironing effect".
Existing studies mainly include a system view based on a central planner optimization.
