This post has been bubbling away for a while. It's partly to do with the stuff that led to the post a while ago about creating Kobolds as a viable class (here), partly to do with the notion of the implicit setting of D&D and what can be done to tinker with it, of which more to follow.
I'm aware that this little more than thinking out loud at the moment; I'm fairly confident that there is a point to it though. The short version of this is something like, "flipping alignments produces a very different implied setting".
Eventually, the standard Tolkien-meets-King Arthur-and-Conan-at-the-Medieval-Fair setting of D&D needs something to shake it up a little. I was wondering about changing the alignments for some common monsters as well as the PC races and working out the implications in terms of setting.
Hobbit - Tibboh (or Gnilflah) - L becomes C
Dwarf - Frawd - L/N becomes N/C
Gnome - Emong - L/N becomes N/C
Kobold - Dlobok - C becomes L
Goblin - Nilbog - C becomes L
Orc - Cro - C becomes L
Hobgoblin - Nilbogboh - C becomes L
Gnoll - Llong - C becomes L
Bugbear - Raebgub - C becomes L
Ogre - Ergo - C becomes L
Hobbits (Tibbohs or Gnilflahs) become evil forest-dwelling imps: Gnomes and Dwarves (Emongs and Frawds) are evil (or at least ambivalent) tribes of subterranean nasties. Dwarves and Halflings are no longer playable races, Instead, players may chose the lovable Nilbog (OK, I know AD&D has Nilbogs but I don't have any rules for them so my Nilbogs are not those Nilbogs), then advance up to Nilbogbohs and Raebgubs, probably; or they may opt for the superficially more martial Cro(s), which become Llongs and Ergos, maybe.
Elves, mostly because of the (at least implicit) existence of Dark Elves and a firmly Neutral alignment, will probably remain Elves - maybe Fle(s) - as a playable race but also a magic-using monster antagonist.
Travs(es)/Travx(es) are another question. Most of my early involvement with D&D was via WD in the 1980s - I'm not sure how much Svarts (and Xvarts) were merely a product of my rather British experience because I've never owned either the MM or the FF so I don't know if they're 'real' in other people's versions. Since, as far as I'm concerned, Svarts as fantasy monsters come from The Weirdstone of Brisingamen (where they equal Goblins pretty much) and The Fionavar Tapestry (where they pretty much also equal Goblins, maybe Orcs, though there are also monsters called Urgach which seem larger and more Uruk-hai-like) I never really had a problem fitting Svarts between Kobolds and Goblins, and treating 'Xvarts' as a wanky spelling of Svart and mechanically no different. Really just playing them as the weakest Goblin-type I suppose.
Svarts hate Hobbits, sorry, Halflings, Kobolds hate Gnomes, Goblins hate Dwarves and Orcs hate Elves. So, Tibbohs must hate Travses (if Travses exist in this new version), Emongs must hate Dloboks, Frawds must hate Nilbogs, and Elves (evil ones) must hate Cros. If a Cro makes it to Ergo-level (about L4 I suppose) they are suddenly also hated by Lahtrednaens for some reason, But they can probably also specialise in magic from there I think.
The PCs, if they don't play humans, will probably live underground and spend their early careers hiding from the sun, as their well-developed infravision means they suffer a -1 to hit when at low levels - both Nilbogs and Cros, but not Dloboks, have -1 to hit at their lowest 'Level', so restructuring the 'to hit' tables along the lines of Thieves or MUs makes sense. Not sure if Dloboks should be a PC race or not. I got on fine without Gnomes (the counterpart of Kobolds), but maybe expanding the Dlobok from a 1/2HD basic monster into a character option could be fun - a sort of affable gremlin that does sneaky and tricksy things (to that end, see the Kobold notes linked to in the first paragraph).
Nilbogs then would be an 'equivalent' to Halflings (though the racial antipathy makes them the enemies of Dwarves) while Cros would be equivalent to Dwarves (though their race-war opposite is Elves).
That might work, but it's the setting implications I think that are most bizarre. The woods and wilds become dangerous places infested by diminutive sling-using humanoids that are excellent at hiding. They're probably at war with the Elves (or maybe not, since a lot of Elves might be evil).
The daytime would be dangerous: the time that right-thinking cavern-folk (Nilbogs and Cros) would hide from the evil Frawds and Emongs, before venturing forth at night to pacify the vast and frightening forests (full of evil Elves and Tibbohs, maybe Lehtrednaens too, with their gigantic leaders) and bring civilisation to them. So thinking of the Nilbogs and Cros as living in well-ordered underground cities and being unused to the uplands might start to suggest something of a potential setting; descendants of those who fed to the underground tunnels when some really bad apocalyptic event happened in the upper world, perhaps (this goes down a rabbit-hole of running a post-apoc D&D where the Orcs and Goblins are the descendants of the survivors in their bunkers, and the 'humans' and everyone else on the surface are the descendants of the unfortunates who were affected by the radiation/bio-chem warfare/nanobots and became mutants).
Other common inhabitants of the forests would probably included evil Nrocinus (I love that word, mostly because it looks like it's pronounced 'Nnn-rocky-nooz'), tricksy flying/invisible Eixips and Etirpses, and the odd Dayrd and Tnaert. As well as Ruatnecs maybe. Many of these would be Neutral so maybe not so different to the rules as written.
Allied races would include the somewhat solitary Ruatonims and Asudems, as well as the flying Yprahs and Elyogrags. I like the name Elyogrags. Later, PCs may be able to befriend a Nogrog or Aremich, which would be something. Then there are the Etydolgorts (another great name), whose ability to blend into their surroundings and fascinate their opponents (causing a -2 penalty to hit unless a save v poison is made) sound like pretty sound guys to have around.
Maybe the easiest way to do this is to list everything with a monster listing and a specific non-Neutral alignment (alignment 'any' will still be alignment 'any' of course) in order and then put it all backwards (so far I've only done the list for Basic)...
Bandit - N/C = Tidnab - L/N
Bugbear - C = Raebgub - L
Doppelganger - C = Regnagleppod - L
Dragon - Black, Green, Red - C = Nogard - Black, Green, Red - L
Dragon - Gold - L = Nogard - Gold - C
Dwarf - L/N = Frawd - N/C
Gargoyle - C = Elyograg - L
Ghoul - C = Louhg - L
Gnoll - C = Llong - L
Gnome - L/N = Emong - N/C
Goblin - C = Nilbog - L
Halfling - L = Gnilflah - C
Harpy - C = Yprah - L
Hobgoblin - C = Nilbogboh - L
Kobold - C = Dlobok - L
(Living Statues come next, and they come in various flavours, but I don't see any reason in particular to alter their alignment)
Wererat & Werewolf - C = Tar-erew & Flow-erew - L
Medusa - C = Asudem - L
Minotaur - C = Ruatonim - L
Neanderthal (Caveman) - L = Lahtrednaen (Namevac) - C
(Normal Humans would mostly be Chaotic according a strict flipping of alignment)
Ogre - C = Ergo - L
Orc - C = Cro - L
Shadow - C = Wodahs - L
Skeleton - C = Noteleks - L
Thoul - C = Luoht - L
Troglodyte - C = Etydolgort - L
Wight - C = Thgiw - L
Zombie - C = Eibmoz - L
What to make of the transforming Eporhtnacyl races (though only Tar-erews and Flow-erews move from Chaotic to Lawful) or the Daednu types - Eibmozes, Thgiws, Notelekses, Louhgs, Htiarws, Ymmums and Eripmavs, I'm not sure. Or Wodahses, which aren't Daednu. Having Clerics able to turn or control Daednu doesn't really seem that useful if they aren't going to be a major opposed monster type.
It's pretty obvious that most monsters listed would go from Chaotic to Lawful; the only real exceptions to this are Gold Dragons, Dwarves, Gnomes, Halflings and Neanderthals. It all becomes a mad mess really. There are far too many C - L swaps there to make this a worthwhile method, but maybe that's just because I took a worthwhile idea and beat it to death (almost literally, moving the undead from Chaotic to Lawful makes no sense and not doing it would reduce the catastrophic effect on balance; also, Bandits pretty much by definition make no sense as a 'Lawful' monster... unless they become some kind of anti-chaos guardian type)... I'll put some work into the Nilbog and Cro classes and see what can be done with those. But it's the setting implications that are the most peculiar result of re-imagining these relationships, I think - they point in strange directions indeed.