Why do you need the TO when you say I suggest to you, but not when you say "I honour you. You can say "I give to you my word" but you can also say "I give to you my word.|
I think you are a bit confused.
OALD describes it: When you suggest something to someone (#1), you put forward an idea or a plan for other people to think about.
When you suggest someone (#2, same page) you tell somebody about a suitable person, thing, method, etc. for a particular job or purpose.
However, even if you suggest something or suggest something to someone, both are fine (#3).
Now about honor
honor to is possible but when it's noun.
honor to something/somebody - a person or thing that causes others to respect and admire something/somebody - She is an honour to the profession.
On the other hand, you honor someone but then it's verb here.
Today, we honor our soldiers
The phrase "I suggest to you" is incomplete. A full sentence would be "I suggest my plan to you", or "I suggest to you my plan" - the second sounds awkward but would probably not be considered ungrammatical by most people.
This full sentence more clearly indicates how it is different from "I honour you": "I suggest my plan to you" has two objects, the direct object (my plan) and the indirect object (you). "I honour you" has only the one object (you), and it is a direct object. Recognising the distinction may help to understand the answer given to the link provided by Fantasier (When does the verb "tell" need a preposition and when doesn't it?).