I think what you're talking about blocks that have physics like sand? This should get the job done. https://www.spigotmc.org/resources/falling-blocks.2913/ It could be outdated though.
Just place a block (stone) in the air, then place a chest on it. then remove the stone. Boom. Floating Chest
It's called Minecraft. Also, you're telling people to be quiet in the most immature way I've ever seen? LOL.