Following up on this, Chest Tracker got an update for 1.20 last week.

I also found clientcommands, which adds some client side commands, including /cfinditem to find items in nearby chests. Though, some of the commands it adds likely considered cheating on a lot of servers (like /cfindblock and /cfind).

IPN is pretty neat. I tried it earlier, and I don’t think it worked with the Iron Chests mod when I checked a couple weeks ago, but it seems to now.

Where Is It, seems to do the same sort of thing as Chest Tracker, but on 1.20.