Why wouldn't you buy a power rack? The best piece of equipment you can buy? So many options. Squat,press,bench,pullups,dips,rack pulls, list is endless.
That would be first on the list and build the gym around that.
Olympic bar
Weight plates
Power rack + pullup and dip attachments
Adjustable bench
If you have extra money to burn, dumbbells
You say you have the cardio equipment already.
Suppose it depends what you are into but the above will see you well.