Second Conditional

If clause-Past Simple refers to present or future ( If I had, If I didn't have)

main clause (I'd hold/ I would hold) would+infinitive

I wish I wasn't allergic to nuts. ( but I am)

I wish they wouldn't make so much noise. (my head hurts and they are making noise)

If only I had the doctor's phone number. (but I don't)

wish/if only+Past Simple- use it when you want the present situation to change

wish/if only+would+infinitive-use it when you want somebody's present behavior to change