Golden cookie effects have a 1% chance of being ultra-powered.
Frenzy: x27 CpS instead of the usual x7.
Lucky: Gain 77 minutes of production or 77% of your cookies in bank, whichever is lower.
Ruin: Lose 33 minutes of production or 33% of your cookies in bank, whichever is lower.
Elder Frenzy: x3333 CpS instead of the usual x666.
Clot: 1/6 CpS instead of the usual 1/2.
Click Frenzy: x1777 clicking power instead of the usual x777.
Cursed Finger: 6 times as potent.
Cookie Chain: Given out in 9s instead of 6s/7s, and will continue until it hits the same amount of digits as your cookies in bank (or if you miss a GC).
Cookie Storm: Lasts for 11 seconds, and you always get 7 minutes from each GC.
Building Boosts: +25% CpS per building instead of the usual +10%.
Dragon Harvest: x60 CpS instead of the usual x15.
Dragonflight: x2500 clicking power instead of the usual x1111.
Sweet!: +7 sugar lumps instead of the usual 1.
Everything Must Go: Buildings and upgrades alike are 7% cheaper for 7 seconds.
RedCookie6666 here, wishing I could post more.
...Eh, whatever. Very little happens on the forums these days.