Self resonance frequency for MLCC capacitor
MLCC devices in surface mount packages all have a self-inductance (as indeed does anything carrying current).

The typical values for some common case sizes:

0402 : about 700pH

0603 : about 900pH

0805 : about 1.1nF

1206 : about 1.4nH

I am also using reverse geometry devices, specifically 0204 and 0306 with self inductances of about 280pH and 350pH respectively.

These are approximations as the effective inductance is determined by the specifics of the actual sizes of the internal plates (which varies across manufacturers).

You can calculate the SRF using the standard series resonance formula and this should be within about 5% (because the self resonance variation is the square root of the LC variation).

[Update: Added calculated SRF and impedance plot]

The part above would be self-resonant at about 43MHz, and here is the plot of Z vs. F:



HTH