what do you do if your gym hasn?t got the equipment you need?
in my case for example chin ups in the smith machine or dips between two treadmills.
any more ideas 
?
Well if you need replacements for certain exercises–go to exrx.net and check out the muscles used in each one and look for substitutes. There are plenty.
How long have you been training that you can’t figure out substitutes? If there are particular exercises you need to replace then name them and someone will help you.
Honestly,
Barbell, plates, and Rack. All else is icing on the cake. You have that andb you can do just about anything you NEED. the other stuff would fall into the want catergory.
But yes getting creative is good I reserve that for nthings like Keg snathces, various complexes etc…
It really comes down to necessity and ingenuity… sometimes instead of normal handles I use towels as the handles on the cable machine to work my grip strength and mix it up a bit.
You’re only limited by your imagination.