Joseph Nebus wrote:

The Hardy prototype was in a Snooper & Blabber short "Laughing Guess".
Not having seen it in many years, I recall that the character was
designed similar to Hardy (including hang-dog look), but without
porkpie hat and the gift of speech.

One would say that a Hokey Wolf prototype was in a couple of Yogi Bear
shorts that were fairy tale parodies. The design was definitely
different, but the personality was there (verbose, pushy) and Daws
Butler had already established his 'Phil Silvers' voice that seamlessly
segued into Hokey a year or so later.

It's true that Yakky and Snagglepuss prototypes made numerous
appearances in the earlier series before Hanna and Barbera deemed them
strong enough to strike out on their own. Alfy was in four YAKKY
episodes- one pitted against Fibber; one against Chopper; two on his
own. Bigelow guested in four different series: Yakky, Snagglepuss,
Augie and Loopy DeLoop. For whatever the reason, Hanna and Barbera felt
the duck and lion would make more viable starring characters than the
alligator or mouse. More story opportunities, perhaps. After having
viewed every Yakky episode on the COMPLETE YOGI BEAR DVD, I couldn't
help notice the variety of storylines. It wasn't ALWAYS Chopper saving
the little feller from Fibber Fox. Some episodes didn't feature
Chopper, Fibber or Alfy.

You may recall a 'monster family' that was in three Snooper & Blabber
and one Snagglepuss episode. The parents looked very similar to Charles
Addams creations (Dad being voiced by Daws Butler in his standard Peter
Lorre imitation), with a croaking toddler patterned bascially as a
mini-Frankenstein monster. After the Addams hit prime time in 1964, the
Flintstones got next-door neighbors in the Gruesomes for a mere two
episodes. Weirdly and Creepella bore a strong resemblance not only to
Gomez and Morticia but the earlier H-B prototypes. Weird continued the
tradition of speaking like Peter Lorre (in this case, by Howard
Morris).

The FLINSTONES Season 5 DVD has a very interesting featurette hosted by
Earl Kress that details the genesis of Hanna-Barbera's ongoing efforts
throughout the first half of the sixties to make series stars out of
these monstrous characters. Unknown to me was that between their last
appearance with Snoop & Blab in 1961 and their heralded arrival on the
FLINTSTONES, a prime-time series featuring these characters was pitched
to ABC- which aired the other H-B prime-timers 'STONES, TOP CAT and
JETSONS. As with most series concepts it didn't make it to the air-
even as a pilot. Vestiges were the two FLINTSTONE episodes.

(It's funny how while the Rubbles lived next door for years, there was
constant turnover in the house on the OTHER side. Alvy Brickrock, the
Gruesomes and Loudrock moved in and quickly disappeared after their
respective episodes. Must be something about Fred that only Barney and
Betty can live next door to him-)

H-B's obsessesion with friendly comedic monsters didn't end there. The
Gruesomes guested in one episode of the 1971 Saturday AM spinoff
PEBBLES & BAMM-BAMM. Similarly designed characters were presented as
members of the Really Rottens in 1977-78's LAFF-A-LYMPICS, albeit
renamed the Creepleys. Dad's Peter Lorre voice remained, for some
reason shared in various episodes by Casey Kasem, Don Messick and Frank
Welker.

In 1980, NBC tried a prime-time revival of the FLINTSTONES, with an
hourlong special concerning the Frankenstones, yet another set of
next-door neighbors. Frank was drawn much like the Frankenstein monster
and had a suitable Bela Lugosi voice courtesy of John Stephenson. The
prime-time revival lasted only for a few more original half-hours, but
NBC retained the Bedrock universe in all-new material on Saturday AM.
The Frankenstones had their own component of the FLINTSTONES COMEDY
SHOW, and often appeared on others. Curiously, Frank was now voiced by
the legendarily prissy Charles Nelson Reilly to humorously incongruous
effect. (Maybe Stephenson wore out his welcome after so many years at
the studio?) An interesting sidenote is that son Freaky was voiced by
Paul Reubens right about the time he was establishing his notorious
Pee-Wee Herman personna. Aside from a lack of his trademark chortle,
Reubens' voice is immediately recognizable.

Even the NAME of a character can endure from one-shot to series, even
if the character is different. One Touche Turtle episode has them
pursing 'Ricochet Rabbit' (whose name sounds very bizarre uttered by
Bill Thompson), who bears no resemblance to the later sheriff
whatsoever: stark naked, no "Ping-Ping-PINNNG" (or any other speech)-
just the requisite speed. When the MAGILLA GORILLA SHOW and its
supporting segments were being developed, it's easy to imagine Alex
Lovy, Tony Benedict, Warren Foster or someone else saying "Didn't we
have a 'Ricochet Rabbit' in some cartoon once? That would make a funny
name for the sheriff."

In hindsight, one could speculate that 1968's WACKY RACES may have been
viewed as a springboard for spinoffs. With ten race cars and two
villians, it must've been hard for the writers to really 'flesh out'
the many characters. If one views the episodes even while blocking out
thoughts of the two spinoffs that did ensue, it's easy to notice that
the Anthill Mob (usually having to disguise themselves to escape
pursing authorities or to thwart Dastardly) and Penelope (an
ultrafeminine Southern Belle racer provides irresistable gag material)
get the most attention of any of the 'good guys'- i.e. the racers. By
virtue of their villiany, Dick and Muttley obviously got far more
screen time- and subsequently their own series as well. Of the other
racers, I can't see anyone other than perhaps #9, Peter Perfect,
getting his own series. Maybe a bumbling, full-of-himself
turn-of-the-century do-gooder who overcomes many slapstick indignities
to triumph through dumb luck.