I found a couple old calculators and their LCD's have about 130 pins.
I was wondering if I can build an LCD driver to reduce the number of I/O pins, because I don't want to use like 14 I/O extenders; or can I make 1 huge extender?
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This answer assumes that each LCD segment is controlled by a separate pin (see comment of Juraj).
With a 74HC595 (shift register) you can use SPI to control 8 outputs. You can daisy chain 4 of them to get 32 outputs with just the SPI pins, to get 128 pins. I assume two pins are for GND and VCC. If you need more than 128 GPIO output pins, than use 5 or more sets of daisy chained shift registers.
Now, since these shift registers use SPI, you can use the slave select to use multiple sets of daisy chained shift registers. I never tried this myself though.
The pins (except GND/VCC) you use is:
The idea is: