Grab armor, but it's 20 frames >.<. Honestly I'd rather go for n-air or u-air OoS, which I believe are 14 and 13 frames respectively at most. Ganon's jump animation is 7 frames right?I've been into OoS for a while, there are some things that can be done. You have your usual shieldgrab, but you can also (much more useful) drop your shield and quickly reverse pivot grab... Your opponent can space himself, but if he has lag, you can nail him with this.
Two TAP JUMP options OoS are of course, the up B and the Quake. Never use the Quake, I find it not useful at all. Your opponent will have to be severely miss-spaced if you want to him with it. Up B OoS is somewhat notable, due to having Grab Armor. Meaning, lagless attacks could be punished - any follow-up could be grabbed (you would still take damage) and your opponent will get a load of damages AND not get their second jump back. This is useful for some characters with bad recoveries and if you're by the edge. The low hitstun on this can get you another hit in the face. Overall not something I would turn Tap Jump off for.
Also, I've now been able to successfully buffer reverses out of shield drop. Meaning, as soon as I drop my shield I can do a turn around jab, d-tilt (with only a bit of practice,) or standing grab.