The Moogle Treasure Trove event begins on Monday which will introduce a temporary new set of tomestones to be dropped from a number of duties within FFXIV.
These tomestones can then be spent on a number of cool items - some new, some existing and some which are (until this event) no longer obtainable. Mounts (2 of which are only usually obtainable from HW extreme primals for example), minions, MGP tokens, Triple Triad cards, glamour stuff etc. There looks to be something for everybody!
The event will run from Monday (30th Sep) until the release of 5.1, which is currently slated for late October. More info here.