For a while I've noticed that a number of small, freely-available games essentially capture the core element of some big fat commercial game, essentially giving you the benefit of quick-learning fast play and no money down to boot.

I wonder if we can work up a list to help people, along the lines of "If you like the [mechanic] in X (or are curious about X) but you don't have the time or want to spend the money, have a look at Y instead."

E.g.

X=Heroquest or Over the Edge
Y=Risus
[mechanic] = Freeform keyword-type descriptors used for character definition and conflict resolution.

X=Feng Shui (?)
Y=Wushu (?)
[mechanic]= ?

X = Burning Wheel
Y = The Shadow of Yesterday
[mechanic] = instant "Hero Point" awards for roleplaying your character's personality

X = GURPS (?), EABA (?), JAGS Revised, CORPS
Y = JAGS 2 (?), EABAlite, CORPS in a Nutshell, GURPS Lite
[mechanic] = detailed point-based character creation and wargame-like combat resolution

X = ? (Obviously SotC, but I wonder if there's another game not by the same authors)
Y = FATE 2e
[mechanic] = ?

X = Unknown Armies
Y = Nemesis
[mechanic] = Madness Meter to represent the effects of mental trauma in terms of both insanity (oversensitivity) and dehumanization (desensitization)

X = Godlike,Wild Talents
Y = Nemesis
[mechanic] = One Roll Engine

X = ? (As with FATE, I wonder if there's some prior game that PDQ neatly distills)
Y = Prose Descriptive Qualities (PDQ) System
[mechanic] = ?

I realize this project/thread is a bit like the type of research/analysis that went into Design Patterns of Successful RPGs, but I'm looking for a list that's more immediately useful to the consumer.

I think you need another slot for genre/setting.  Its a bigger draw for me than any rule mechanic.

For what it's worth, you can get a free version of EABA called EABAlite in PDF at this link.

Also, a free version of HARP Lite is available here.

Thanks. I was aware of EABAnywhere but not EABAlite. And I agree it belongs in the same slot as JAGS-2. I'll amend that entry. About HARP, hmm...what distinguishes it? I'm not trying to include every free/lite game, just those games which distill out the key ingredients that distinguish bigger games. Ideally in, say, 10-20 pages for rules proper and maybe a few dozen pages tops for listings of skills & such. I don't know much about HARP other than it is somehow related to Rolemaster and MERP...and as for those, my impression of the selling point was the chart-based combat system. I don't mean to cast doubt on the quality of HARP but if there isn't a one-sentence answer to "what particular innovation does this game offer, that sets it--or its 'family of designs'--apart from other RPGs", then I don't know if I'd include it. After all John Kim already has an extensive list of free RPGs, many of which are the introductory or "lite" version of commercial games.

Another criterion for inclusion here would be general applicability for the GM who's looking for a system to use in a homebrew campaign, and would either like a "lite" version of something that's known for a certain specific mechanic, or a way to preview certain concepts before investing the time and money in a fullblown game.

Essentially, I'd like a list that gives the end result of a fairly common conversation:

A: I'm looking for a game that does [some nifty thing].
B: You should totally check out [X].
C: Or if you don't want to mess with 200 pages of rules and a ton of book-keeping, you can just use [Y].

Quote from: StumpydaveI think you need another slot for genre/setting.  Its a bigger draw for me than any rule mechanic.

Okay, I think I get what you mean. E.g., "You were intrigued by Privateers and Gentlemen, but you'd like to have time for other things in your life? Try In Harm's Way."

That would be a useful list, I agree...but it's not what I'm trying to do here. I urge you to create another thread for that purpose.

Quote from: Elliot WilenAbout HARP, hmm...what distinguishes it? I'm not trying to include every free/lite game, just those games which distill out the key ingredients that distinguish bigger games. Ideally in, say, 10-20 pages for rules proper and maybe a few dozen pages tops for listings of skills & such. I don't know much about HARP other than it is somehow related to Rolemaster and MERP...and as for those, my impression of the selling point was the chart-based combat system. I don't mean to cast doubt on the quality of HARP but if there isn't a one-sentence answer to "what particular innovation does this game offer, that sets it--or its 'family of designs'--apart from other RPGs", then I don't know if I'd include it.

Hm.  I think I see what you're going for.  HARP was designed independently from Rolemaster, but designed from the ground up with the idea of staying compatible with Rolemaster.  

As to it's merits, it's a very customizable open-ended percentile system combining some of the best features of level-based and point-based games.  I can't really think of any other game that does that except Rolemaster, and it isn't as customizable as HARP.  HARP is much less complex and more cohesive.

HARP Lite is a full 90 pages.  Basically, a free version of HARP that has some of the advanced rules and spell lists left out.  Still fully playable, though.

Hm. Another way of putting it is I'm looking for "The poor man's X" for various values of X.

Not sure I'd put HARP Lite on the list but based on your description it sounds like RM-MERP-HARP might be in the same "family" as Dragonquest and/or Talislanta (at least 2nd edition).