The most profitable crafting courses are Blacksmith, Goldsmith, Alchemist and Culinarian. The advantage these classes offer is that you could provide highly preferred gear ffxiv gil, furniture, consumables along with materials available. Most players will never take the time to flesh out their Disciples on the Hand classes, creating this a highly advantageous sellers sell for nifty crafters happy to put in the work.
Many players don't want to put in the effort to craft basic products which they regularly need. Consequently, there may be often a consistent interest in even common crafted items with the Market Board. If you need some Gil fast, this is an easy to earn profits. That being said, the more expensive your crafting levels become, there more Gil there's to be made.
At virtually any point in FFXIV you will find trends in items needed to the new content. Leveraging gathering and/or crafting to get together and/or create these things will always be the most effective sources of income. Similar to player housing, players with property are going to be eager to buy such things as Oriental Grass Plot along with other items, including Sabotender and Chocobo Topiary, to wear their gardens. Some of them can only be acquired through airship missions, so you will find there's high demand for the kids but restricted supply. It's not easy to farm for these products, but if it is possible to get them you then should be able to offer them on for just a tidy profit.
Players desperate to explore the revolutionary content to be had in Stormblood are going to be in great necessity of potions, ethers, elixirs, stat buffs and virtually any devices an alchemist might make. As is usual once you get your expansion, there will likely be players ESO gold needing to rush from the content as quickly as you can, which means are going to buying potions and so forth in droves rather than taking some time to craft the things themselves.