With the content drought in late patch situations cosmetics usually become a much better market than in early patch situations. With the playerbase putting less stock on character power on average now is the time to get some cosmetics to sell.
Mounts are better than transmog
Mounts always sell better than transmog in my experience. Mounts are generally more noticeable than than individual transmog pieces, and with a smaller number of mounts in the game compared to transmog they are a more attractive item type to collect. That makes them great for goldmaking during downtime periods, as well as a great staple to just keep on the AH.
Crafted and farmed mounts
There are both mounts that can be farmed or flipped, such as the world drop mounts from BfA or the world event mounts, and mounts that come from crafting professions. Generally speaking the crafted mounts are more consistent, as even for old world materials the supply is usually consistent enough that you can make good gold. The dropped mounts are less consistent, either due to limitations in when you can get them such as for the event mounts, or the difficulty involved in farming for them due to high RNG.
Engineering has access to mounts from a wide variety of expansions, all of which are good. The main ones that I try to keep in stock are the motor cycles from Wrath, the rockets from Mists of Pandaria (one each for Gnomish and Goblin Engineering, so you want two engineers), the sky golem from Mists and lastly the ATV from BfA.
Xiwyllag ATV is great
This mount deserves it’s own chapter as it is a little special. To craft it you need to craft one component each from Engineering and Blacksmithing. Then you combine them to craft the mount. Both recipes drop from Mechagon, so you will have to take a trip back to BfA. I’m not sure how easy it is to solo, or if you need a good bit of gear to do it, but the mount itself sells really fast. Competition is very low on this one, as the engineering part requires expulsom. Expulsom is as annoying to craft as ever (you have to craft tidespray linen bracers and scrap them in the scrapper in your factions main city in BfA), so you will only ever be competing with players that can be bothered to head back and do it. Getting both recipes is very well worth it, so definitely look into this recipe.
The Vial of the Sands
This has over time been the holy grail of crafted mounts. The recipe is a drop from Cataclysm archeology, and is incredibly annoying to farm. This has typically lead to a relatively low competition, and very healthy profit margins. If you want to farm it I’ll refer you to my old guides on this mount as things have not changed, you have to be ready for a large amount of RNG, and potential frustration. If you do get it, you can look forward to some very healthy sales numbers though.
The recipe is for alchemy, so keep that in mind. Since 8.3 you can get a reputation discount on the required materials, by farming the Uldum Accord rep, alternatively if you are horde you simply need to get a goblin into Uldum. This will save you a ton of gold and is almost necessary to make gold on these mounts right now.
The last group of mounts is from jewelcrafting, the panthers from Mists of Pandaria. You get the recipes from the Order of the Cloud Serpent in the Jade forest. These require expensive vendor materials that usually make the profit margins fairly thin, but they are still a strong addition, and on smaller servers they will often spike up higher after someone decides to run a reset. You will need alchemy to really make a profit here as you can usually transmute the gems for significantly less than they cost straight up, and for a lot less effort than prospecting Ghost Iron Ore.
Start working on the recipes and keep them on the AH!
Time to start working on obtaining these recipes! I like to keep about 2 of each mount on my banker at all times. They don’t sell all the time, but i do get sales very consistently, so get on it!