On Skyblock, OpPvp and Survival, from my knowledge, have the /auction plugin. I think Hellblock should have it as well. It would help people trade easier and get a bit more money. You're probably thinking "Tyler, just use chest shops!" but not everyone knows what a chest shop is. Once it took me 10 minutes to explain to someone what a chestshop was. I think adding /auction to Hellblock, as well as those that have it, would be a good idea.
I do ;p But not a lot of other people do.. Use the shop sign plugin to create your shop then advertise it only a bit.
Support, it would boost the economy, and would improve the communication between buyer and seller in a way. But in my honest opinion I think Hellblock should be removed as a gamemode. It is almost always empty, which means it just makes the server lag heaps. Mineverse would be better without it honestly, But this is just my opinion.