About ID_SD and ID:SC pins...
There is only possible to attach PI-HATS?
Or can I attach just an EEPROM like FM24C08B?
I know a similar question has been asked before.
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You can't use GPIO 0/1 as an I2C bus on the Pi3. On the Pi3 I2C bus 0 is used internally.
You can use GPIO 0/1 as ordinary inputs and outputs on the Pi3.
There are no restrictions on earlier Pi models, you can use GPIO 0/1 as ordinary GPIO or as an I2C bus.
This assumes that you do not have a HAT fitted which is using GPIO 0/1 for its own purposes.