I know i can… come one say the bad word… … CRAFT it.
But i want to find it while doing bosses too. I recognized that for example Duriel has a very tiny lootpool now. Havent seen a single Tibaults dropping from her. Even Mini-Bel just drops the exactly tiny loot variation that Duriel drops.
Is it now a drop that can only drop while fighting Superior Lair Bosses? 
I have found 2 tibault charms and one 850ilvl tibault with the worst possible stats
It’s one of those uniques with lower droprates than everything else I guess
what if we could reverse-craft the unique charms.
tibault’s will charm + 3 ancestral white pants = ancestral tibault’s pants
Unless something changed, Tibault’s is in the general loot pool. Meaning, it can’t be target farmed from anything.
The only sources are very rare random drop from anywhere in the game, or crafting it.
Crafting it is the much easier source.
I can remember Duriel having a really nice a nd wide unique lootpool.
Now its (farmed with barbarian):
w/o any additional drop from the general unique lootpool.
Same drops from Mini Belial who was always a nice source for uniques of the general pool. He only drops what Duriel drops.
After 90 Duriels runs i can confirm:
Use your balls friend, I gambled only just over 1 page of pants with OBOLS.
From this I had 5 pants that were white or blue ancestrals.
Cubed them to remove affixes and/or upgrade to unique, now I have Tibaults.
That’s the results of my test. Your luck may be different of course!
update: ended up getting 2, that means you can use one but keep one for when your ‘upgrade’ to mythic turns it into some other random bs 
I bet it’s same issue with Temerity pants, drops are much rarer now there’s crafting.
Also just got mythic tibaults from UC mythic tribute run, I did select ‘more armor’ option as well. So this is another thing to try, obviously very random.
I have saved my UC Trib Runs for next week. They will adjust the drops a bit
DUUUDE, Tibaults will is like The HARDEST PANTS TO CRAFT I SWEAR!!
It’s becoming as bad as enchanting (and you know how I feel about that).
I swear!
I laugh at gender hangups, so this is just out of curiosity… is it a German thing, or do you think of Duri as a ‘she’?
Duri is the bro, and Andy is the sis, afaik. 
New creeper boss drops it pretty often
only way i got one after 100 hours or so was using the cube to gamble to convert whites to unique. even then, it took 40+ tries to get a badly rolled one. this particular unique is super rare as an actual drop for sure.
Kill the new boss, it drops Temerity.
For Tibaults, get some blue/yellow pants from the Obols vendor, remove their afffixes in the cube until it turns to a white item, then upgrade to unique.
What about Airidas Inexorable Will? It can’t be crated into a charm and I know I’ve crafted at least 25 mythic rings and I haven’t seen a single one.
Every season its the same process with these stupid pants. Gamble white/blue anc’s. Cube the pants. I managed to get them faster this season after 3 pages worth of pants….
My last drop was off the seasonal boss and it was an ancestral. Sadly it had two bad affixes so I’m stuck with lightning resist but they’re out there. Lightning actually isn’t bad if I have to wear an elemental resist.
Temerity drops very often from Harbinger of Hatred.
I dropped a couple tonight from the reaper boss. They are account bound though.
for some odd reason I have found 9 of them. not all acc bound , since i gave 2 away. I didnt not use cube to try gamble one.