I'd like to know whether i have to use the preposition commonly used after verbs such as go and wish when the latter are at the end of the sentence.
e.g. this is the place i love to go (to?) / i know what you wish (for?)
Your first example is fine without "to", whereas your second example is ambiguous without "for". It has more than one meaning:
Ex: I know what you wish.
Meaning 1: I know what you want me to do.
Meaning 2: I know what you wish for.
All the best.