This sentence is not grammatically correct. It should be:
Here are three more sentences that we could say are in some sense "unclear," which is to say, sentences that make us feel we have to work harder than we think we ought to (or want to).
Note that it should be "make" and not "makes" since "sentences" is plural and not singular.
"Here are" is not the main verb. The main verb is "are" from "to be". "Here" is an adverb of place which you say to indicate where something is physically located or to indicate that the things which follow demonstrate what you are talking about.
This sentence is quite long and could be rewritten as any of these:
1. Here are three more sentences that we could say are in some sense "unclear". That is, these sentences make us feel like we have to work harder than we think we ought to (or want to).
2. Here are three more sentences that we could say are sort of "unclear". That is, these sentences seem like we have to work harder to understand them.
3. The following three sentences are sort of "unclear". That is, these sentences seem harder for us to understand.
I think sentence #3 gets right to the point without using words which really only serve as filler words.