Q:

Are there any spells that heal hit-points over time in Pathfinder or 3.5?

I've been looking through all the Paizo spells, but all I see so far are instantaneous duration healing (cure) spells.
What I am looking for is a spell I can have on a wand or other magic item, so if such a magic item exists already, that would be a sufficient answer.  I would prefer a low-ish level spell, but if there are none, there are none.
What I am not looking for is feats or class features that allow this.

A:

The vigor spell line in Complete Divine and Spell Compendium is your go-to in 3.5. The line consists of:

the 1st-level lesser vigor for Fast Healing 1
the 3rd-level vigor for Fast Healing 2
the 5th-level greater vigor for Fast Healing 4

They each last 10 rounds (one minute) plus a number of rounds equal to your Caster Level. There are also the 3rd-level mass lesser vigor and 6th-level vigorous circle for group healing, with Fast Healing 1 and 3 respectively.
Lesser vigor, in particular, is a 1st-level spell that is the most efficient HP-by-spell-level option in the game, healing 11 HP at CL 1. Therefore, wands of lesser vigor are pretty standard adventuring gear for folks “in the know:” it’s the most HP for your gold piece you can get.
In Pathfinder, the 1st-level infernal healing spell is nearly equivalent to lesser vigor (it lasts only one minute, rather than one minute plus CL rounds). However, strangely enough, it is [Evil]; this makes it harder to use as “standard adventuring gear,” but for healers who don’t mind the alignment issue, it’s still the best option. There is a celestial healing spell that is [Good], but it has a massively-reduced duration that makes it basically worthless. There is also a greater infernal healing and a greater celestial healing which work like greater vigor (Fast Healing 4), but are 4th-level instead of 5th-level. There are no group-healing options among celestial/infernal healing spells.
The difference in duration means that a wand of greater vigor is more cost-effective than a wand of greater infernal healing, but it costs more up-front, requires a higher-level crafter, and takes longer to heal. The point is largely moot as lesser vigor and infernal healing are both much superior in that regard, though. The duration on both celestial healing and greater celestial healing makes them worthless.
And then there is song of healing for bards, which grants fast healing 2 as a 4th-level spell to up to 3 targets. Considering it costs a 4th-level spell slot and only works in conjunction with a bardic performance, you would be better off just leveraging your Charisma to Use Magic Device some wands of lesser vigor.

A:

In Pathfinder there is a spell called Infernal Healing (Inner Sea World Guide) that gives fast healing 1 for one minute.  I can't give you any answers about 3.5
Since answering this there is now a Pathfinder counterpoint to Infernal Healing--Celestial Healing (Player Companion: Arcane Anthology).  Though instead of lasting one minute, it lasts one round per two levels--making it nearly useless at low level, and only slightly useless later on.

A:

There are pre-existing magic items that do this. From the d20 (3.5e) SRD:

Ring of Regeneration heals 1 HP per level, per hour. Also regrows severed body parts. Price: 90,000 GP
Ring of Rapid Healing gives Fast Healing 3 (heals 3 HP per round). Price: 300,000 GP

