RMMZ I was wondering if there is a plugin that shows the battle HUD in the overworld.

[Castanera]

I'm trying to make a dungeon crawler and I thought that having the party's HP and MP visible the whole time would be good.

Something similar like this
http://www.hardcoregaming101.net/megaten/smt-psx1.jpg

 

[Htlaets]

Should start by saying what maker you're using but Sumrndmdde's hudmaker is probably what you're looking for.

 

[Trihan]

VisuStella just recently released a HUD plugin that does exactly this.

Frontview Battle UI VisuStella MZ - Yanfly.moe Wiki

www.yanfly.moe

 

[Mcniner]

SumRndmDude's hud maker is exactly what you need.