What polyfuse should be used with Raspberry Pi Zero in a larger board circuit? Look to the Raspberry Pi B+ or original Raspberry Pi schematics for guidance. Then, you simply search around for a part with similar specifications to use in your own circuit. One design note in particular, you should place the polyfuse immediately after your power input source. Your first isolating capacitor should come after the polyfuse.
20191127/DuckDuckGo raspberry pi zero polyfuse
20191127/https://raspberrypi.stackexchange.com/questions/61302/does-raspberry-pi-zero-have-a-polyfuse
In particular, the MF-MSMF200 is used on the Raspberry Pi A+, a 2 A hold polyfuse with 4 A trip.
20191128/https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/rpi_SCH_1aplus_1p1_reduced.pdf
The original Raspberry Pi used a 750 mA hold polyfuse with 1.1 A trip.
20191128/https://elinux.org/RPi_HardwareDuckDuckGo raspberry pi polyfuse
20191128/https://www.element14.com/community/thread/19575/l/f1f2-polyfuses-gone
20191128/https://elinux.org/RPi_Hardware