There are a lot of dictionary (most of the time obscure) domains available under .com.
Should you register them ?
It all depends.
Certain niche words may have value if you work in a specific industry or have connections (possible end users). If you are looking to resell it would be advisable to stick to the industries you are familiar with, or you are going to end up with too many useless words on your hand.
OVT and google results should be taken with a pinch of salt.
Let's just take on example:
occlusion
9,310,000 results in Google.
This a word that is often used in medicine but in other fields as well. Does it have potential ? Probably not a lot as it is too focused and not really usable.
Despite the fact that it's registered in major TLDs.
Use your common sense. One good domain should be
usable to have any potential for resale.