I was only tracking what I *haven't* done, so I need to go back and confirm what I have done and obviously will take questions in case I've forgotten something.
Negative statements
Titles: Missing 100
Brown Mage Guinea Pig
Triumphant Owner
Victorious Owner
Winning Owner
Leather Lauder
Loom Lunatic
Shell Scrimshander
Bone Beautifier
Knitting Know-it-all
Master Academic
Master Healer
Master Hunter
Master Hussar
Master Privateer
Master Tamer
Established Examiner
Transcendental Tamer
Glorious Groomer
Monke-Onke Master
Leviauthority
Mog Gardener
Nilotican Decimator
Very Discerning Individual
Marmorkrebs Mauler
Mboze Mauler
Ongo Obliterator
Raskovniche Render
Curator Culler
Alexander Annihilator
Sidhe Smasher
Lilith Liquidator
Dread Purger
Fulmination Disruptor
Quieter of Ancient Thoughts
Draconic Interloper
Banneret
Ballistar Royale
Bronze Ballistar
Final Ballistar
Gold Ballistar
Mythril Ballistar
Rook Buster
Sable Star
Sagacious Star
Saintly Star
Sapphire Star
Savage Star
Scarlet Star
Searing Star
Shadowy Star
Silver Ballistar
Singing Star
Slicing Star
Sneaking Star
Sniping Star
Sonic Star
Soothing Star
Speaking Star
Spiritual Star
Sprightly Star
Stippling Star
Striking Star
Summoning Star
Surging Star
Swaying Star
Subduer of the Trolls
Subduer of the Undead Swarm
Subduer of the Mamool Ja
Legendary Alchemist
Legendary Blacksmith
Legendary Boneworker
Legendary Culinarian
Legendary Goldsmith
Legendary Tanner
Legendary Weaver
Legendary Woodworker
Armory Owner
Boutique Owner
Curiosity Shop Owner
Furniture Store Owner
Jewelry Store Owner
Restaurant Owner
Shoeshop Owner
Accomplished Blacksmith
Accomplished Boneworker
Accomplished Carpenter
Accomplished Chef
Accomplished Goldsmith
Accomplished Tanner
Accomplished Weaver
Consort Candidate
Ballistager
Fortune's Favorite
High Roller
Preventer of the Second Coming
Every Ilm a Heroine
The Triumphant
Lux Ex Tenebris
Extremely Discerning Individual
Mimic Masher
I believe that gives me 973, actually. 974 if I've ever done Ramuh on VD and just forgot about it because his title is broken.
Quests: Missing 27
* Bastok - 3 missing
* ToAU + 3 completed suboptimally, but all complete
* WotG - 1 missing (Succor to the Sidhe)
* Abyssea - 23 missing (Martellos)
BLU: Still missing 32 spells
Campaign Ops: 95% complete
Fish: Missing 58
Furniture quests: I'm not sure how many I am missing. I have recently done all but 9, but I probably did the rest already.
Moogle Mastery A, B, C: XII, XV, XI
UNM: Have not killed Tolba, Glazemane, Brambrox, or Tumult Curator.
Reisenjima Goblin: Missing 2 Balrahn Eyepatches and the 2 sets of Skirmish wings
Vorseals: Missing Tumult Curator and the 160/240/360 kills of Azi Dahaka and Naja Raga
Skills: I have capped all my skills pre-Mastery levels except Chocobo Digging (probably rank 6) and Synergy (still 20). I also got 147 Mastery levels and skilled up to cap across a lot of different skills.
Mounts: I am missing Moogle, Spectral Chair, Buffalo, and Red Raptor
Trusts: I am missing Mumor 1 and 2.
Master Fights: Missing all of them (+ Mimic)
Positive statements:
Adventuring Fellow: Capped and flippant.
Missions are complete.
MMM runes are complete.
Odyssey: I cleared all of T1 up to V20 and some of Tier II, then I have V0 clears of most of T3 and T4.
Meeble: Complete with max stars.
Playtime: ~1770 days, 8 hours
Assist rank: Bronze
Monstrosity: All to 99, I think. I will check. Dang I loved Monstrosity.
Mastered jobs: 16 (could be inferred from titles, but why not state it)
Maps: Have all of them that one can keep permanently
Incursion: KI is only 128
Voidwatch: All done, including Provenance
Takeaway
My big takeaway here is that you don't really have to do the hardest content in the game to hit Mastery Rank 8. I've basically skipped everything that would be considered genuinely difficult (Master fights, some Odyssey clears, the VD BCs that aren't duoable, etc.) and I still made it.
I would be unsurprised if it was a pure title count + some small amount for skills and playtime. I believe my playtime is much higher than Avereith's was when he hit 8.