please name the i2c devices you have tested or using

PN532 - NFC/RFID MODULE

• integrated 4.7k pullups

• used module PN532

• on ESP8266-04,12E/F

• D4 - SDA and D5 - SCL

works only with clock stretching by @Frida, have to run some more test and then will create a PR

>print(nfc.getVersion());
{
  "chip": "PN532",
  "firmware": "1.6",
  "support": 7 }