Could I get IBIS model for an analog IC (op amp or regulator)?

Operational AmplifierLDO Linear RegulatorsDC/DC Switching RegulatorsCommon

IBIS model is generally fitting for an input / output terminal behaivior model of the digital IC.

It is generally used the signal integrity analysis at 10 MHz or more logic systems.
Therefore, It is not used for analog IC. It is recommended to see the IBIS OPEN forum for details.