Minimum RC to keep OpAmp Stable
Procedure

(1) determine the output inductance of the OpAmp in the gain configuration

(2) compute the dampening resistor, as Rd = sqrt(L/C)

(3) if you do not like the value of Rd and the amount of dampening (just a bit of overshoot permitted), you can change the Cvalue or change the OpAmp or change the gain

How to determine the output inductance?
You opamp AD8607 has 400khz UGBW. The datasheet says Rout at 10Khz, gain of 1, is 36 ohms. At UGBW the Rout will be 36 * 400KHz/10Khz = 36 * 40 = 1,440 ohms.
And the ADI datasheet has this plot, validating the method we just used:


What inductance? Freq is 0.4MHz. 1milliHenry and 1MHz is 6.28*0.001*1E6 = 6,280 ohms. At 0.4MHz, 1milliHenry is 6,280/2.5 = 2,500 ohms. Our inductor is exactly 1mH * 1,440/2,500 ~~ 0.6milliHenry.

Suppose you have 1uF as Cload. Rdamp = sqrt(L/C) = sqrt(0.0006H/0.000001F) = sqrt(600) = 24 ohms.

In this screenshot, we use Signal Chain Explorer to verify. UGBW = 0.4MHz, Rout = 1,440 ohms, Gain = +1.0. The 24 ohm Rdampen is lower right corner BODE plot.



[ responding to chupacabras question: is output impedance = output inductance? ]
This screenshot illustrates the INDUCTIVE output impedance of the opamp with Rout of 1,440 ohms {set in the SCE GainFollower Worksheet}, UGBW of 0.4MHZ, and DC_gain of 100,000. The gain drops to 0.707 of DC, at 4Hz. Do we see onset of strong inductive slope at 4Hz? Yes. I set up the UnityGainFollower, and click on
the topcenter "OutZ" to generate plot for Output Impedance / Resistance / Reactance over entire frequency range [here 0.1Hz to 1GHz], then edit plot frequency range to cover only 2 decades. (in this circuit, clicking "Local OutZ" produces the same plot as "OutZ", looking backward into selected stage.)

Notice the 2 middle plots, covering 10Hz to 1KHz and 1KHz to 100KHz, have identical shape. The Zout in each increases 100:1 as frequency increases 100:1, which is inductive behavior.