For example, the attributive adjective only and pronoun one: can we say "there is only one"?
Pronouns do not normally allow internal pre-head dependents. *"Extravagant he bought a new car", for example, is completely impossible. I say 'normally' because there is one minor exception, the use of a few adjectives such as "lucky", "poor", "silly" with the core personal pronouns:
"Lucky you! No one noticed you had gone home early".
"They decided it would have to be done by poor old me."
There is a restriction, though: the pronoun must be in accusative or plain case (compare "poor old me" and *"poor old I")