i guess for the purpose of showing some sign of life in this thread...
i actually have a couple favorites of the ones i've learned so far.
1)(halfscreen) j.C cl.5C 6A hd cl.5C 6A 214AC>214P (623Axx214A)x3 623A 2363214ACxx2141236AC
is a recent favorite. its kinda not worth it since its only 940 damage for 5 bars but i like that its a relatively non-situational version of his first 100% combo which is:
2)(corner) CH j.CD 6B hd 6B 214AC[whiff]>214P (623Axx214A)x3 623A 2363214ACxx2141236AC
this combo, to me, is one of the coolest. sure it isn't really that practical and getting the ex rekka part is kinda inconsistent but it really opened my mind to the possibilities of situational confirms. furthermore, learning this one is extremely helpful in teaching you things about the character's workings. it shows that iori's 6B, A dp and the second hit of rekkas (without the first) scale much less than many of his other moves and are very helpful in building damaging combos. the dp into rekka section is actually a lot of fun to do (surprisingly), although its been made more or less useless with the discovery of empty cancels. it overkills with 1012 damage from CH fulljump CD and just barely squeeks by with a cool 1000 damage off of a CH hop CD.
3)(corner) j.C cl.5C 6A hd cl.5C 623Axx236236A 6B 623A 623C[2 hits]xx214P>214P 623C[2 hits]xx2363214Pxx2141236AC
with 937 damage for 4 stocks this is probably the most worthwhile corner hd to learn if you're tryna hit for damage without having/spending 5 bars or being able to EC. it shows the lack of heavy proration on the second hit of the fireball super as well as showing that there is a slight difference between the A and C versions of said super. it also shows some pretty interesting things regarding ex iori's A dp and how it affects juggle-ability when A) not cancelled into and B) is connected with at certain points in the attack (i.e. the grounded portion).
EDIT:if you are actually in possession of/willing to spend 5 meters, then you can EX the super before max-cancelling for 975 damage.
there are a lot of other good ones but these are my favorite three that don't involve EC. on a loosely related sidenote, i do believe certain evidences support the notion that it is not actually a glitch but was added to this character specifically on purpose; perhaps as an homage to older KOFs.