What should I do with multiple 5V to 3.3V voltage regulators?
Since each board was designed separately odds are that each regulator is rated only for the chips each board includes.

The first board might need some 100mA to work and have a regulator that can go up to 150mA, and so on. It's possible that none of the regulators you already have is capable of supplying enough current for all the chips you are planning to put on the same board.

First of all you need to compute the total power consumption of all the stuff you want to put on the board. You find the values on the chip's datasheets of course, use the higest value if you are not sure. The sum of all the currents needed by the various chips will of course be the max current the board will require. Add another 10 to 20% as a safety coefficient, then look the regulator's datasheets: probably none of them can supply that much current. Finally search for a "stiff enough" regulator and use it.