My list mostly dual/multiclassing:
1.Rogue+Fighter+Arcanist
2.Palladin+Fighter+Rogue
3.Shaman+Rogue
4.Cleric +Rogue
5.Druid+Rogue+Cleric
6.Ranger+Rogue
7.Ranger+Arcanist
8.Barbarian+Arcanist
9.Barbarian+Rogue
10.Duelist+Arcanist+Rogue
11.Inquisitor+Rogue
12 Inquisitor+Fighter+Rogue
13:Druid+Rogue
14. Shapeshifter (Rogue+Assassin+Mage)

Best Character Races and Possible Class Combos:
Goblin with Druid and Rogue class
Lizardfolk with Arcanist+Fighter class
Goblin Shaman+Rogue
Shapeshifter Race Options:
Undead
Dark Elf
Lizardfolk
Shapeshifter Main Ability and Specific Class Sets
(Rogue+Assassin+Mage) or (Rogue+Assassin) or (Inquisitor+Assasin+Rogue)

Ideally
Race:
Dark Elf
Classses:
Shapeshifter Possible Classes in addition to abilty to shapeshift
1.Inquisitor+Assassin+Rogue
2.Rogue+Assasin
3.Rogue+Assassin+Mage

Ideal combo for gathering information and infiltrating enemy lines:
Race:
Dark Elf
Main Ability:
Shapeshifter
Main Class:
Rogue-Assasin

I'd be interested in artificial races, whether scientific or magical in origin. Golems and androids come to mind, as well as living machines.

UNDEAD and also clockwork

My Idea of a class, is a Necromancer Archetype.
Class Description of Soul Devourer Mage (name is not very good ^^;):
There are Necromancer that go on the 7th full moon every year on the Graveyard to search a fallen hero or villain. If the necromancer found him, he take the best parts of the body and extract from the muscles/ brain the "(Special)-moves and stored it in rune glasses.
The body part from what he extract this, is stored. After years - some say more than 40th, the Necromancer have from all the stored body parts a complete body, that he connects with magic to a vessel (like a golem).
After this step he wait for the 24 full moon of the year, and make from the extract "(Special)-moves a serum. On 12pm this serum must be drunk by the necromancer, to takes his life with this serum.His Soul go after that to the prepared Vessel, because the body of the heroes/ villains have a strong connection to the "extracts".

Now the "Soul Devourer Mage" have a new body and lost his necromancer-skills, but dont lose his mana. With the new body he won the Skills from the "extracts". Because not every heroe/villain have the same body/skills, the "Soul Devourer Mage" can be good in fighting and magic, or will be a much stronger Mage.
The special of this class is, that this body is dead - so he cant die. If he die, he only lost a extract/ bodypart and revive with lowered power.
The strongest of this class have waited many years to get more than 50th body parts....

Sorry for my bad english :/ I hope someone like this idea :)

Since I have found a somewhat new understanding of goblin culture due to a fantasy book I am reading. I would like to add Goblin or Hobgoblin to playable classes. Just a few games let you be a goblin and I have never seen a playable hobgoblin.

For a race or even a class I had always loved the idea of doppelgängers creatures that can change to another species to disguise themselves and copy some (not all) of their enemies characteristics or abilities during combat and older doppelgänger with more levels can copy higher level abilities or characteristics or/and more of them.

Goof-off:
* Abilities resemble that of a rogue.
* Play-around (Ex): The goof-off can choose to play around. When using this ability, roll percentile dice and look it up on a table what happens.
* Critical play-around (Ex): If the goof-off rolls a natural 1 when attacking, roll on the play-around table; whatever action is rolled is what the goof-off does instead of making that attack.

(Note that perhaps the ability list might be a bit more bard-like and less rogue-like, depending on one's interpretation.)

Monster cook!

Scour the world to discover, defeat, and consume terrible creatures!

Just killed a tentacled horror from the Abyss? Sauté that with some shallots and a tangy soy sauce!

Defeated an iron golem? Melt him down and make some quality cast-iron pots and pans!

Brought down a gigantic snail? Better whip out the butter, garlic and several loaves of bread!

Why stop at the local eatery when you can make your own food, on the go?

P.S.: Monster cooks should never consume sentient creatures.
P.P.S: Mosnter cooks should never consume other sentient races.
P.P.S.S.: Monster cooks should not consume the undead.

A Damphir a-la Vampire Hunter D or Blade!

Vampire (fallen) paladin: has become that which he despises, now on a mission to redeem himself by finding and killing the master vampire of his line whilst dodging other vampire hunters. Spoiler alert: condition turns out to be irreversible but it takes a lot of questing to figure that out...

Well as a race i would like to see Lizardmen or Ogres. As class i would like a Necromancer.

What I loved about the RPG system "The Dark Eye" is that it offered tons of customizable character classes, constantly updated either in class specific rulebooks or local guides. For example there is a country modeled after the Frisian coastal region, and it actually gives you a character sheet for a levee builder true to the historical original.

In that sense, maybe the class of wandering quack of a certain region. Some lore and social skill, with a bit of combat.

Or a grave robber as a variant of the thief class, with lore and magic knowledge instead of the pickpocketing skill.

I'd like to see the Brawler hybrid class (Monk & Fighter) or the Sacred Fist archetype for the Warpriest. These 2 are a nice alternative to the Monk with alittle more flexibility and flavor

I would love to see a class that involves dealing with the manipulation of physics, like gravity, speed, and force. Pair that with a very well-schooled person (like a wizard) and that would be super fun to play.