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He loves.
I’ve read some things about intransitive verbs, recently. Can “He loves”. be thought of as a complete sentence, and grammatical?
And, can
A wind comes.
and
He has.
be thought of as complete sentences, and both grammatical?
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Usually the verb "loves" takes an explicit object. But it is not necessarily so. For example, some theists might answer the question:
What does God do?
by saying
He loves
In any case "he loves" is a full sentence.
Yes, your examples are complete sentences and grammatically correct. Contexts in which these sentences would sound natural may be rare to nonexistent, but syntactically they're fine.
He has doesn't usually work as an intransitive construction, but it works as an example of ellipsis (omission). E.g.:
"Has your brother cleaned his room?"
"He has [cleaned his room]."
To love is not intransitive, nor is it ditransitive. Aside from religious lingo, most people who hear the "sentence"
He loves.
...will feel lost and be anticipating a direct object.
I'm curious. In what context are trying to use such a "sentence?"
You're other two example sentences, however, are absolutely correct!
Although, your third sentence.
He has.
requires a context in the perfect tense.
Has Joe eaten?
He has.
On the other hand, if you simply say.
He has.
Listeners will immediately anticipate the question
He has what?
To come is intransitive and doesn't require or expect a direct object. If anything, it may expect a destination, or an entire clause.
He comes bearing gifts.
They came riding in on horseback.
You come along.
The wind comes. // Better to say the wind is coming, but still it's correct.
