I understand that the original title of LG was metal-halide.net.

But why does it still exist as a browsable carbon copy of LG?

Additionally, why do these exist..?

https://pjc.name/index.php
https://ia800105.lighting-gallery.net/index.php

Interesting! Also, metal-halide.net just leads to lighting gallery.

How did you find these?

I understand that the original title of LG was metal-halide.net.

But why does it still exist as a browsable carbon copy of LG?

This is not rare in fact. Just two domain name records configured to point to the same server IP.

rrk@fedora:~$ nslookup www.lighting-gallery.net
Server:      127.0.0.53
Address:   127.0.0.53#53

Non-authoritative answer:
www.lighting-gallery.net   canonical name = lighting-gallery.net.
Name:   lighting-gallery.net
Address: 50.28.48.225

rrk@fedora:~$ nslookup www.metal-halide.net
Server:      127.0.0.53
Address:   127.0.0.53#53

Non-authoritative answer:
www.metal-halide.net   canonical name = metal-halide.net.
Name:   metal-halide.net
Address: 50.28.48.225

In real life, things may be a bit more complex, as two or more different web sites may still be grouped with the same server IP address, the way cloudflare works, but here it is not the case.

Additionally, why do these exist..?

Owner just decided to keep old domain for some reason. For example old lost domain names (no more paid for) are often recycled by bad people who use them to run some shady advertising (drugs, casinos etc). You don't want to lose your reputation that way.

Some time ago I was searching obscure lighting stuff w/google and the metal-halide.net came up as well as lighting-gallery. So I thought cool, not only an LG member had that item in a gallery but someone else on metal-halide did. But they were identical.

Recently I googled "George Liv Photo" to find where (or if) I had posted stuff. pjc.name/index.php, ia800105.lighting-gallery.net and an old photobucket came up.

How did you find these?

In real life, things may be a bit more complex, as two or more different web sites may still be grouped with the same server IP address, the way cloudflare works, but here it is not the case.

Owner just decided to keep old domain for some reason. For example old lost domain names (no more paid for) are often recycled by bad people who use them to run some shady advertising (drugs, casinos etc). You don't want to lose your reputation that way.

I doubt a former LG owner is paying for these extra domains. Not sure but...
When a domain name expires, such as when a payment period comes up and the owner doesn't renew, the domain name provider can register that unpaid name as a blackmail selling tool, sometimes placing that web name for sale at 10x the normal cost. What's unusual is that, instead of a blank page saying This Domain is for sale, the metal-halide and pjc re direct to LG. So not sure what's happening.

Some larger companies also purchase misspelled domain names. This is so that when you make a common spelling mistake when entering the address, it will redirect to the correct website. It also prevents someone else from using it for a competition website. For instance, Apple Computer has an active website address of apple.com. However, it also has aple.com. If you use the latter in the address bar, it will redirect you to the former.