We have no clue what to buy, are the Seemingly Special Timeworn Maps the most valuable thing we should shoot for? The armor set looks like ERP faggot bait and aside from maybe a couple of the mounts (kamuy maybe?) nothing else on the list immediately grabbed our attention.
Donut Earring and Great Serpent of Ringa are exclusive glamours.
The Gwiber and Kamuys are pretty easy to farm through PF, you won't even need PF for the Lunar or Euphonoius Kamuys.
Buying dungeon gear or housing items is never worth it because they don't put Ultimate BiS sets in there, and getting triple triad cards is almost never worth it (It was for the Warrior of Light card, but that's a special case.)
The Drake and Laurel Goobbue also aren't really worth it, just deal with the beastmen for a few weeks to get them.

This is the hairstyle. If you don't want it, it's still worth selling for a fat stack of gil.

This is /malevolence aka Ballroom Etiquette - Dark Entreaty.
I don't have a picture for /scheme but that emote is a lot harder to get because Eureka hates you in particular.
The Twice Stricken orchestrion roll is from E5N.
Alte Roite isn't worth getting because it's a guaranteed drop from something that was soloable in around 4 minutes as a Warrior last expansion.

If you actually care about Bardings, you might want to get this for your Chocobo. Remember that we once Kweh-d.
The real prize for every single Irregular Tomestone event are the Seemingly (Gazelleskin), Ostensibly (Zonureskin), Potentially (Kumbhiraskin), and Concievably (Ophiotauroskin, has not shown up in any event so far) Timeworn Maps.
They cost 15 Mogstones each, and have two key differences from their standard counterpart.
They're stackable, and they have a 100% instead of ~50% chance to open a portal.
I'm getting the Seeminglies because they're the level 70 ones and Gazelleskins are considerably more expensive than any other kind of Timeworn Map (Unless it's week 1/2 of x.0, x.05, or x.3)