So I thought I would share these tips for newer players, and also with the hope that any old school players can add any tips or correct misconceptions or errors herein. There are a few things I have not experimented enough with yet to be sure of considering that online information is often wrong per Uthgard. Being friendly with as many mobs as possible can sometimes give an edge in a solo/small man fight so I have been trying to figure out how to maximize friendlies out in the frontier. This really isn't issue for group running but if you are a hunter, blade, skald, or general soloer you might want to look into some of these points.

Midgard Frontier - This is one I have not yet made a determination on as I killed a great number of vendos on my main character. Killing Arachites in Spindehalla will raise Vendo faction. It is easy to juggle other faction to maintain friendly with Arachites while you do this if needed. Note the bugs in frontier are on Frozen Web faction so no way to get in good with them. Theoretically bone eaters in Midgard Frontier are vendo faction so you should be able to go neutral with them vis a vis this method. This gives you some camps of mobs to hide/take refuge in when set upon in our realm. I'll get to this eventually but if anyone knows for sure this works please shout out.

Albion Frontier..

Cyhraeths...albs like to bot/afk xp/farm these. Per online info the faction is Mountain Boogies...you default neutral to them and there is no way to raise faction. So ensure you never kill one, nor a fiery fiend, gridash, gytrash, freybug...etc. Being able to stroll through their spawn enroute to hitting some albs is helpful. I assume the online info is correct, but am afraid to kill one of these to check.

Ellyls/Twyleth Teg - These factions are opposing so killing one raises other. Personal choice as to which to friendly with. In populated days of yore Ellyls were good to be friendly/neutral with for purposes of catching alb groups at the spawn. Ellyls are fairly confined to one location however, with a couple exceptions and twyleth are more spread out across the zones so it may be a factor in your decision. Going nice with Twyleth and Fellwood can help you if operating at the Alb Stableman near Surs.

Grimwood vs Fellwood - again personal choice. Grimwood, grimwood keeper, Treefalls are the harder mobs but localized to one particular spot. Nice place to hide/hang out in if needed but fellwoods are spread out throughout the frontier somewhat with multiple spots you can find some sanctuary assuming your opponent doesn't have that faction. Side bonus from choosing fellwood is that killing grimwoods also boosts isolationists of Albion faction. You are default neutral to this one though so you shouldn't need the boost.

Ravenclan - Possible to get in good with the clan by killing archer mobs in Forest Sauvage. These mobs are in an area to east of Castle Excalibur. There is a problem here that is more serious in hibernia versus this case, but if you are already level 50 it may be difficult to pull this off easily. These mobs are low and there possibly is only one mob you can kill if level 50. The mob must con non-gray, green or above to get a faction hit/boost. Rob Ria is the mob that will still con at 50 so if you want to turn Ravenclan neutral you will need to camp him a few times, assuming you have never killed a giant you will only have to farm him 20 times or so but definitely time consuming if you havent fixed this faction while you were a lower level. Recommendation, visit this area at 35-40 ish and kill the archer mobs.

Pictish Druid - tired of getting cast on or dropping speed running from port to Beno? No sweat, get in tight with these picts over by Hibernias portal keep in Hadrian's Small ruins there with Priestesses/Templars....kill them a short while and picts will go neutral. There is also an annoying pict at the Snow/Pennine choke corridor who can be ignored by doing this. Sadly cave fairies have no faction and must be dodged.

Hibernian Frontier -

Noting this as something to be aware of, not sure if Hibs exploit it much but they have such a powerful opportunity that they should never lose group fights in Breifine. Numerous high level purple mob groups are at various strategic locations, Fomorian faction. Impossible for us to boost this faction as the mobs to do so are all hib home zone mobs.

Leprechauns - if your character is lower level and not 50 you can kill cluracans to get in tight with Leps. Hibs like to xp/farm these especially near Scaith. Hotbed of activity with RR6 Guardians of Lame logging in there to hit the hibs. Lep friendlyness is a must. If you are already 50 go to Gorge and west of relic keep is Clurican Aquavitors....30 minutes of killing and enjoy your new Leprechaun allies.

Empyreans - You default neutral to these and want to maintain it. They are not the highest level mobs around but there are some good spots with numerous mobs clustered.

Curmudgeons - Quick neutral by killing Siabra factions (see below) can ease running around or give you a spot to hideout. Be aware though that their camps contain Curmudgeon Foresters which probably due to an Uthgard deficiency are not on Curmudgeon faction. These will remain hostile and remove some of the benefit of going neutral to Curms.

Siabras - Mainly a hib home zone faction however I tried to get friendly with them for a specific reason and ran into an issue. Far Darochas are on their faction list and there are a couple spots where it is nice not to get jumped by an orange/red con mob while scouting or running around. Thus the desire to go neutral with them. Theoretically the following should work...kill siog raiders which will boost Emp and Curm and lower Siabra. Then go kill Emp to boost Siabra and lower Emp. Then kill a Curm to boost Siabra and lower Curm. The net effect should be maintaining of Emp and Curm faction and plus one to Siabra. While time consuming that method should work, however it does not here on Uthgard. Not sure if it is an Uthgard "Feature" but when I kill the Emp or Curm they seem to lower faction by 2 points, in other words I have to kill siabras faction twice to maintain Emp/Curm faction which causes this procedure to actually lower Siabra faction. Thus if you are 50 you are screwed as far as I know. You should be able to give up Curm faction to go neutral with Siabras though possibly.

If you are lower level the following might work, I am currently in process of testing it with a mid 30s. Go hibernia and kill any members of the Sprite Rebellion faction - rage wolf, anger sprite, wrath sprite - kill many many many of them till Emps go friendly. Then kill Emps back down to neutral - this should raise Siabra - repeat ad nauseam with goal of keeping Emps neutral. Theoretically you should eventually go friendly with Siabra this way...then you can kill a few Siabras to friendly with Curms and should have all 3 neutral and above. Again this should work, but can only be accomplish pre- level 40 and there is no telling considering this is Uthgard whether it will work or not.

That's all I have, if you know any other tips/tricks for faction please post and let me know.

Great post.
I'm not aware of any errors in what you've said here.

[EDIT: There is an error in the OP regarding necro mountain mobs: Mountain Boogies, which do indeed include Cyhraeths, appreciate when we kill Isolationist mobs. I just went from neutral to friendly with the Cyhraeths by killing a bunch of Isolationist sorcerers, wizardesses, etc. Then i went back to killing Grimwoods to atone for my sins.]

[EDIT 2: The homeland mobs i'd planned on killing to achieve neutral or friendly status with the curmudgeons are unhelpful... Neither tidal sheeries, the named tidal sheeries Scaird and Aessa, nor the elder tidal sheerie nightspawn near Druim Ligen, nor greater dew sheeries outside of Innis raise curmudgeon. Not one. As far as i've found, the highest level mob that raises faction with the curmudgeons without simultaneously aggravating the siabra is the sheerie urdsummoner, a land sheerie in Cliffs of Moher. The highest i've seen it seems to be about lvl 28, so all my higher toons are screwed as far as curmies go. Unfortunately there wasn't much thoroughness regarding factions on Allakhazam back in the day, so many, many mobs don't have their faction associations listed and i cannot tell whether the higher level sheeries are meant to be as unhelpful as they are on Uthgard. It seems odd, though, like the curmudgeon foresters who are fixed on aggro, that all the low level land and water sheeries (up to 25 or 28) raise faction with curmudgeons, but the higher level ones don't. Dew sheeries, in the same camp as greater dew sheeries, raise faction with the curmudgeons. So do grass sheeries, moss sheeries, but... not moss monsters in the frontier. And rock and stone sheeries, but not earthshakers. Once again the higher level monsters are factionless.

The tidal sheeries aren't factionless, though... they simply have a feud running with the koalinth, so if you, like me, kill koalinth by the quadrillion, you can go for ages trying to lose your friendly status with tidal sheeries, and end up tired.]

[EDIT 3: Twylyth is a typo. It is Tylwyth. The faerie frogs near Hurbury are also in Ellyl faction, so killing them at a lower level is one way of getting neutral/friendly with the archers sprinkled throughout Pennine Rollercoaster zone. /bow to the Reaver who killed my templated lvl 25 Champion there, and i really must go and petition the gods about my debuffs - not a single one landed, while his DoT and DDs did. Maybe Arawn is just much more powerful in that heathen land.]


HIBERNIA
This is what i'm doing: Kill curms while leveling until siabra are friendly (i always go for friendly since quests often require killing these and it makes it easier to stay above the aggro threshold) and Angered faction anytime Empyreans are neutral/aggro (I do occasionally kill empyreans for drops, including the decent OTD bow), and Sheerie (Hib homeland mobs) until curms are friendly. [Edit: this last step must apparently be done well before lvl 50. I'll double check and update again.] Obviously this won't work if you can't find sheeries in the FZ, [or if the moss-monsters and earthshakers are oddly factionless] but since my heart has always been in Hibernia i weep pityless tears for those of you stuck trying to juggle these without the 'help' of sheeries.

Individually i've tested each of these faction changes, but i haven't done the whole thing in sequence yet on one toon to get Curms, Empyreans, and Siabra all friendly. Yes, i've been killed or slowed down by far dorochas a few times.

By the way, what are the mobs that raise Fomorian faction? I haven't ever noticed any, although i have a vague notion if there are any they are in Shrouded Isles. Neither ZAM nor Mads' bestiary lists any as of now.
viewtopic.php?f=9&t=38903

I did notice killing the Fomorian Underlings and Maol lowered faction with the Parthanan rather than the Fomorian, and wasn't sure if that is as intended or not.

Though it pains me to do it, i'll mention that killing loghery men also garners favour with the leprechauns. They're higher level than the aquavitors, but they're much closer to your portal keeps, you invaders, you.

MIDGARD
The Battlegrounds are useful for the Arachite vs. Vendo thing. Thidranki and Caledonia have plenty of both. (Decius and other skeleton mobs in Cale are Arachite faction. Go figure.)

ALBION
I don't know, may edit or add a post later in this thread.

Confirmed:
I've tested both of the following:
Kill Curms to get neutral or better Siabra, then Sheeries to get neutral or better Curmudgeons. This only works for Hibernian toons. Empyreans are default neutral anyhow.
Kill Siabra to get neutral or better Curmudgeons, then Empyrean to get neutral or better Siabra, then Angered to return to neutral with the Empyreans.
These must be done well before hitting 50. The first one should be started right away in the teens, and finished by lvl 30 or so. It can be done entirely in the safety of the homeland zones. The second one should be done from about lvl 20 to be completed before lvl 40, and can be done mostly in Mt. Collory or Cruachan Gorge.

My preferred pattern in Albion FZ now is to kill Forest Archers to get chummy with the Ravenclan, kill Tylwyth to get appease the Ellyllon (or vice-versa), kill Grimwoods and Treefalls to get friendly Fellwood (doesn't affect the Forest Sauvage Fellwoods, but by your mid-upper 40's, only the golden and silver fellwoods in Sauvage will aggro, and they were default aggressive to begin with), then kill isolationists to get friendly Grimwoods.

Isolationists have a 0% chance to aggro despite becoming 'aggressive', which is a feature, not a bug, if we are to accept what was in the Prima guides and elsewhere.