Entity Finder

How would I do that with mApex?

Make another script or add it to it's hook.

Also, could you give me a link to the gamemode? Or maybe the server IP, so I could look at it.

I play at all of the servers...

But I play at this server mainly: 192.223.26.11:27016

How would I do that? Sorry if I'm being a nuisance.

Iterate though all entities, check their class.
If the class matches the one you search for (exemple: 'dz_item'), just get it's World Space Center and use a World to Screen function to get the screen coordinates of the entity. Then draw a simple text at throses coordinates (exemple: 'DayZ Item').

I attached to this post everything I got from some DayZ mod server (imperius server or whatever), it could help you, look at entities (located at gamemodes\dayz\gamemode\plugins\items\items). (To moderators: the attached archive only contains lua files, I don't think scans are required.)

I might make a basic esp for it, depends if people have an interest in it. Otherwise it's not hard to do one yourself.