Right on the Moon Guard and Wyrmrest Accord community forums there are threads to sell and trade names. Now, of course these being roleplay servers, we do tend to take our names pretty seriously. These threads have been up and active since 2020 and 2019, respectively.
Opportunic, yes. Exploitive? Not in the slightest. It’s not harming gameplay or hindering it. I don’t even play Classic or Progressive Classic so much, only when the whim takes me, but I was there when the realms opened to hold names and I absolutely grabbed the names for my Retail RP characters who I had planned to eventually level at the time. I still hold those names to this day, without too much leveling have been done. There may come a time when I really decide to go in and actually do something with those characters or I may not. But they’re my characters and my names I’m clinging to. That may not sit well with some folks, but I was there first and I beat everyone to them. It may be that it ticks some folks off immensely, but I was there when they weren’t to take the names before they could.
I’m sorry you’re just coming back to find that some name you’d like isn’t available - but c’est la vie. Check the realm’s forums for a similar name list. Reach out to the owner if there is such a thing. You’re welcome to try and barter with that person - but I’d highly suggest you not go in ready to argue that what they’re doing isn’t “legal” or fair. They’ll block you and that’ll be that.
Good luck to you.