a lot of the promoters talk about 'options' in contracts anybody shed any light as to what these may be? in general or any specifics from contracts
It simply means that the winner is contracted to the promoter for a number of fights after the event.
A rematch clause is a rematch clause. If you want 'options' to literally mean every conceivable option that could be included or excluded from a contract then I guess it could, but commonly when a promoter demands 'options' then that is what is meant.