Such a feat was used in Kotor 2, and worked out rather well.
But, that was a video game, even if it was based on the d20 system.

In "Races of Destiny" there is a feat that allows you to spend 1 point for any skill, even if it is cross-class, but it does not raise the maximum number of ranks you can have in the skill. It's good for generalists and high-level characters, who don't need to "max out" all their skills. I think it's called "Able Learner" or something like that.

There are other feats that allow you to pick any one skill, make it a class skill for yourself, and also give you a +2 bonus with that skill. I think it may be called "Cosmopolitan" and it's from Forgotten Realms. A similar feat allows you to pick 2 cross-class skills to make class-skills, but there's no +2 bonus.

I think that's your options, in a nutshell.

I figured someone had to have come up with this already; thank you!

We live to serve ... MAN!

JT

it is called Able Learner; however, you MUST be human to take it, and you can only take it when you create the character.
Alternately, there's a Ravenloft feat called Reincarnated that you can take for one skill only, but you also have to take it when you create the character.

There is one.
It's a Forgotten Realms one;

"Cosmopolitan(general):
Choose a nonexclusive skill you do not have as a class skill. You gain a +2 bonus on all checks with that skill, and that skill is always considered a class skill for you.
SPECIAL: You may take this feat multiple times. It's effects do not stack. Each time you take this feat, it applies to a new skill."

It's a 3rd ed rather than 3.5, but I don't see any real harm in it.

In 3.5, it was changed to a regional feat (available only at first level and only to PCs and NPCs from a certain region) in the Player's Guide to Faerun.

Cosmopolitan (Regional): You've been lied to more times than you can count. This history has made you intimately familiar with the deceit, guile, and double-speak of city folk.
Prequisite: Dwarf (Waterdeep), Elf (Waterdeep), Half-elf (Waterdeep), Halfling (Amn), or Human (Amn, the Golden Water, the Sword Coast, or Waterdeep).
Benefit: You gain a +2 bonus on Bluff, Gather Information, and Sense Motive checks.
Special: You may select this feat only at 1st level. You may only have one regional feat.

NERFed!

Quite, but it makes a lot more sense considering 3.5 as a whole.

Education (makes all Knowledge skills class skills) has been released in a few Core and FR books.

I would also consider making similar feats such as Bohemian (Perform), Artisan (Craft), and Entrepeneur (Profession). For the other skills that don't have subsets, I would grant the ability to use a feat to make any given skill a class skill (Tumbler for Tumble, Pick-pocket for Sleight of Hand, et cetera). It's worked out well in my campaign.

The problem with this idea is that these other skills you list don't limit themselves to which subsets may or may nto be class skills like Knowledge does. Just about everybody gets craft, and all crafts. And near every class has profession too.

Then the player's won't take the feats.

I don't see what you're saying about limiting subsets.

I'm talking aboutspecific Knowledge skils are listed as class skills while others are not, but for the other skills that have subsets (Craft. Profession, and Perform) it's either the whiole skill or nothing. I did have a hard time making myself clear there.

A character taking large numbers of Knowledge skills is likely doing so to make her character either an expert in one or two specific fields (The Planes and Religion, for instance), or is just trying to meet the prequisites of a prestige class.

The same goes for Craft, Profession, and Perform. Also, with the exception of Perform (in the instances of Dervishes and Bard-based classes), these skills simply aren't as good for an adventurer to add to her pool of skills (allowing for outlying instances).

Just because some classes have some Knowledge skills already available to them doesn't make Education any worse of a feat as the player's are the ones picking their feats to begin with. Alternatively, you may want to give them a +2 bonus to Knowledge checks that were already class skills for them.

Again, this is just what I've found works in my campaign.

The Human Paragon has a class feature of this sort. It allows him to pick one of his class skills and make it a class skill for any class he has.

I don't see a problem with making a feat of this type. Pick any skill and it is a class skill for whatever class you have.

I wouldn't go with the above and give it a +2. That's just silly and unbalanced, to me unless it has a prerequisite.

We use a version of the Cosmopolitan skill (as shown above- the non Forgotten Realms version).

Here's 2 house rules for my Charm campaign:

2-for-1 Customization Rule: Upon creation, a character may drop any two class skills from his/her class skill list, substituing a new class skill of the players choice. For example, a cleric who (as part of his backstory) spent a lot of time sneaking around the abbey as a novice may take 'move silent' as a class skill, dropping 'diplomacy' and 'knowledge: arcana'.

3-for-1 Customization Rule: Upon attaining a new level, a character of any level may drop any three class skills from his class skill list that he has never put ranks in and substitute a new class skill of his choice.

Not a bad house-rule, I must say.

I dont know how 3e works so I really can't say. When ever I had an idea simualr to this I wrote a few things down and then did some test runs on it with one or two of the players while waiting for everyone else in the group to show up.

-and I suddenly think, "When I get home, I have to post about this new idea and see what everyone thinks!" Albeit this reflecting I'm a bit geeky when this is the euphoric moment of my day.

:) Nothing wrong with that.