Once you reach exalted with BfA reps, the mission table is next to useless. Waste of resources for measly Azerite gains and even measlier amounts of gold.
I have sold a few pets cross-server, mostly Holiday pets like Naxxy that are still new enough to be popular. Since I have a character or 2 on an old server who can farm the Tricky Treats easily enough, I can then sell them on the server I now have for my main characters. Pet prices are actually pretty similar on both even though the old one is Low population and the new one is Medium.I did buy some of the more rare pets and a few mounts, when I moved my main from that old server to the new one where I have friends, along with some stuff that was fairly valuable at the time of the Character Transfer (early Legion). I actually made out really well! I made close to double the gold I had converted into items to get below the Transfer cap, and I still haven't sold any of the Mounts and only a couple of the pets. Character Transfers are expensive enough that they aren't really an efficient use of Battle.net Balance for Gold-Making purposes, but since I was doing it anyways I am really glad (and proud of myself) that I took advantage of the opportunity! A few investments were a bust, but I did my research and compared prices to see what I could make a good margin on (a lot of Chaos Crystals and Hexweave bags, it turned out), and then made sure to sell them in a trickle and not a flood to prevent prices from dropping. That whole process taught me more about gold-making than any other experience. Sure Warlords and Legion mission tables were amazing, but they were effectively mindless. I miss them dearly, but while they were easy they weren't exciting since there was essentially no risk at all.