Getting a mountThis list is by no means exhaustive; let me know if you've found a good source.
PermanentThe best way to get a mount is to have one by virtue of a class feature or feat.
- Animal Companion (Druid): One of the most powerful options. Everything about the druid class is hax, were you expecting any less here? The downside is that you'll need to worry about Handle Animal to control it, unless you combine it with a familiar or special mount (which gives it an Int above 2).
- Animal Companion (Ranger): Not as good, but still respectable. You get an animal companion at 4th level, and use only half your ranger level to calculate its abilities.
- Animal Companion (Prestige Ranger): That's better. This PrC gives you a druid-strength animal companion from lv1. Plus it counts as ranger for most purposes.
- Animal Companion (Beastmaster PrC): As druid, but add 3 to your class level for determining abilities. Stacks with Druid levels for a very powerful companion.
- Buy (gp): You can simply buy a mount with gold - the prices are listed in the PHB. The warbeast template lets buy any creature to serve as a mount but they're ridiculously underpriced, so make sure your DM knows what you're doing.
- Cohort (Leadership feat): The Leadership feat gives you a second character 2 levels lower than yourself. Yes please.
- Cohort (Dragon Cohort feat): Who doesn't love dragons? And in particular, who doesn't love a 3-point reduction in LA for their scaly friend? If your mount is a dragon there's no reason not to pick this feat over Leadership, unless you want an army of followers.
- Dragon (Dragon Steed feat):
- Familiar (Wizard/sorcerer): Familiars usually aren't powerful (or large!) enough to make reliable mounts. They don't get many feats, and their hp is half of the caster's d4 - that's just pitiful. Their ability to share their master's buffs, however, means that they can take advantage of most of the ways the caster has around his own fragility problems - they can do pretty well if polymorphed into something, blurred, etc.
- Familiar (Attain Familiar feat): A duskblade has d10 Hit Dice, so his familiar can actually have decent hit points. Most non-Core arcane casters don't have the same number of buffs though. Note that the familiar from this feat derives its abilities from your caster level rather than your class level - normal familiars aren't advanced by levels in PrCs.
- Familiar (Improved Familiar feat): While this feat can make your familiar large enough to serve as a mount on its own, it can also be used to open up new types for alter self and similar spells.
- Griffin companion (Aglarondian GriffonriderUE): As meaty as a special mount, with double-speed progression but fewer special abilities. Also it's ginormous.
- MagebredECS warhorse (Order of Rekkenmark affiliation5N): Good at low levels, since you get it essentially for free if you write the order into your backstory. The free 4th-level bodyguard at lv1 is kind of cheesy though. Unlikely to get by many DMs.
- Party Member (Friendship): If another PC is a horse, then good for you. After all, real men ride each other. Can be very powerful if you get the means to share buffs somehow.
- Psicrystal (Psicrystal Affinity feat): Usually preferable to a familiar. Psions and psychic warriors may not be as powerful as wizards, but the psicrystal's feats, average BAB and hardness give it a big advantage over the familiar, and share pain is a nice buff. The disadvantage is that there are no larger psicrystal variants, so unless your character is very small you will need the metamorphosis spell to convert it into a ridable form.
- Thrall (Thrallherd PrC): Thralls are like cohorts, but always loyal. A thrall is also one level lower than you rather than two. And if you reach lv10 in the PrC you get another one! The only downside is that you can't combine thrallherd with Leadership. This may not apply to substitutes like Dragon Cohort, but your DM is likely to breathe fire on you if you try it. If you have a psionic build, try to fit a level of thrallherd in instead of Leadership.
- Wild Cohort (Wild Cohort feat): Functions more or less identically to an animal companion, but a little less powerful. Grants access to the Silverwood Arcanist PrC for spellcasters.
SummonedIf you're looking at using a summoned creature for a mount, duration is important. If you're using your mount for travel rather than just for combat then a duration of 1 round/level isn't that useful unless you can summon some kind of robot horse with rockets for legs. Bear in mind that you will have to spend actions to get on the mount. And watch out for
dispel magic.
Class features- Special mount (Paladin): It's a summon, but it lasts 2 hours per paladin level and can be used 1/day, meaning that you can basically keep it up all the time. Of note, according to the DMG you can designate a cohort as your special mount for +2LA - the rules are unclear on whether this creature must be summoned or sticks around.
- Of special note is the lightbringer paladin ACF from Expedition to Castle Ravenloft, which lets you trade your first weekly use of remove disease for a continuous death ward effect on your mount. If you have 6 levels of paladin this is always worth it.
- Special mount (Prestige paladin): Requires two levels rather than five, one of which advances a divine spellcasting class. You have to wait a few levels to get in - as compensation, your mount's abilities are calculated as if your class level were three higher.
Spells- Astral construct (Shaper 1):
- Gate (Wiz/Sor 9, Clr 9): High-level, cheesy, short duration and requires concentration. Pass.
- Mount (Wiz/Sor 1): Summons a light horse or pony. You can use this from lv1, and it lasts 2 hours/level. Eventually you can summon enough of these for your entire party and keep them up continuously. You can't summon warhorses with this spell, so this is mainly for travel.
- Phantom steed (Wiz/Sor 3): Lasts half as long as mount, but the "horse" it creates is super-fast, can go just about anywhere, and looks cool as hell. It doesn't attack, but it doesn't panic in combat either. Plus "animals shun it and refuse to attack it", which might extend to its rider as well. Gets better with the Knight Phantom PrC (Five Nations) which boosts the CL and gives you extra castings per day. It normally takes 10 minutes to cast, but Knight Phantoms can cut this down to a standard action.
- Planar ally (Clr 4/6/8): Your ally can remain for a number of days, though you need to pay gp and xp.
- Planar binding (Wiz/Sor 4/6/8): Like planar ally, but cheaper and a little more dangerous.
- Summon monster
- Summon nature's ally
VestigesTransformedIf you don't have a creature you can ride, turn something else into one. Many transformative spells have restrictions based on creature type, so that should be the most important thing to bear in mind when choosing a base creature. Many of the same caveats apply here as with summoned creatures - the difference is that if the polymorph runs out you'll still have an ally of some kind.
Some candidates (such as a druid cohort) are capable of transforming themselves, while others require you to cast spells on them. The Share Spells ability makes this significantly easier.
I am the mount!If you're getting a cohort/thrall/etc. it's definitely worth considering making
him the rider and yourself the mount. Alternatively, if your minion ends up significantly more powerful than you (as with the Ubermount and Big Guy Is With Me builds), it might be more enjoyable to play the minion as the main character and the "master" as a tag-along.
On a related note, certain races like centaur count as being mounted at all times due to their anatomy.