Here are the links I have found most helpful.

[EmBee]

Specific Sites:

Baby Face Dolls
http://babyfacedolls.com/

Barbie Horses
http://www.mattel-pferde.com/

Bitsy Bears
http://littlestpetshop.50webs.com/bitsybears/bitsybears.htm

Carousel Collection
http://www.modelhorsegallery.info/m/Matchbox/MHCs_Matchbox.html

Charmkins
http://www.chanth.com/charmkins/index.html

Cherry Merry Muffin
http://www.merrymuffinland.net/
http://www.nijirain.com/Lady-ToysCherryMM.htm
http://www.toycollection.de/sammlungen/cmm/cmmeng.htm

C.U.T.I.E.
http://yowiemaggi.homeserver.com/yowiemaggi/monsters/cutie.htm

Cutie Club
http://www.kmlautanen.fi/en/toys/ccident/ccmain.html

The Dark Crystal Merchandise
http://www.lauraknauth.com/MovieCollectibles/DarkCrystal.html

Disney Dolls
http://www.donettas.com/main.html

Small Disney Figures
http://yowiemaggi.homeserver.com/yowiemaggi/even_more_am/disney_index.htm

Fairy Tales
http://p.etal.tripod.com/ftidentification.htm
http://fairytailscollector.com/main.html

Fantasy Fillies
http://www.fantasyfillies.com/

Fashion Star Fillies
http://www.fashionstarfillies.com/

Giga Pets, from member zuse!
http://virtualpets.cjb.net/

Glo Friends
http://www.80stoysale.com/glofriends.html

Grand Champions Horses
http://www.angelfire.com/on/raventyde/grandchampion.html

Keypers
http://www.80stoysale.com/keypers.html

Kidgetts
http://littlestpetshop.50webs.com/kidgetts/kidgetts.htm

Kinder Surprise
http://yowiemaggi.homeserver.com/yowiemaggi/kinder/kinder_surprise_index.htm

Kitty Kitty Kittens
http://www.pranceatron.com/kittens/kittykittykittens.html

Lady Lovely Locks
http://ladylovelylocks.org/merchandise

Li'l Miss Dolls
http://www.crowncombo.com/articles/2007/014_lilmiss/lilmiss.html

The Lion King Merchandise
http://www.catsnthings.com/lionking/

The Little Mermaid Merchandise
http://www.littleariel.com/gallery.htm

Little Pretty
http://www.48ovvi.org/littlepretty/

Littlest Pet Shop, from member zuse!
http://www.littlestpetshop.50webs.com/

Maple Town
http://mapletown.tripod.com/toys.html

Mimi & the Goo Goos
http://www.nwi.net/~noteboom/Mimi/?Home

Monster In My Pocket
http://yowiemaggi.homeserver.com/yowiemaggi/monsters/monsters_muscles_index.htm

Moon Dreamers
http://www.fortunecity.com/athena/dance/275/moondoll.html

My Little Pony (G1)
http://www.ponylandpress.com/
http://www.kimsites.net/dreamvalley/index.html
http://home.intranet.org/~maggi/mlp/
http://www.unicorn-tarpan.net/pony/info.html
http://mlppreservationproject.webstarts.com/index.html
http://www.greatponies.com/

My Little Pony (G2)
http://www.angelfire.com/80s/ponymarket/
http://gen2.aien-hime.com/

My Little Pony Fakies
http://the-fakie-hideout.weebly.com/index.html
http://letsplayponies.tripod.com/lanardinfo.htm

My Pretty Mermaids
http://www.mayanbutterfly.com/toyidguides.html

My Pretty Mermaids - Read "Wave Dancer Is Missing!" Online
http://alpenfieber.blogspot.com/2010/01/my-pretty-mermaids.html

Pocket Critters
http://www.javys.com/takara/

Polly Pocket
http://www.onlypollypocket.com/

Popples
http://www.80stoysale.com/popples.html
http://www.80stoysale.com/popplesads.html

Precious Places
http://www.thisoldtoy.com/fisher-price/dept-7-playsets/o-precious-places/a-index-pp.html

Princess Gwenevere and the Jewel Riders
http://www.darah.com/collection/jewelriders/

Puppy In My Pocket (and more)
http://vintage.talviuni.com/
http://yowiemaggi.homeserver.com/yowiemaggi/even_more_nz/puppy_in_my_pocket_index.htm

Quints, from member zuse!
http://tycoquints.50webs.com/

Rainbow Brite
http://www.rainbowbrite.net/
http://www.80stoysale.com/rainbow.html
http://wharble.com/Rainbow_Brite_Collectibles.htm
http://www.wix.com/galacticatt/rainbow

Rugrats Merchandise
http://superyo.nuxit.net/Razmoket/objets/objets-e.html

Sailor Moon
http://www.qserenity.com/dolls.htm

Sea Wees
http://seawee.tripod.com/seawees.html

Spice Girls (Band) Dolls
http://spicegirls.jemmagic.com/dolls_originalgp.html

Strawberry Shortcake
http://www.strawberry-shortcake.net/collectorsguide.htm

Surprise Pets/Friends
http://sites.google.com/site/timpersock/

Wish World Kids
http://www.dukenostalgia.com/Kscope/Wishworld/WiW_index.html

~

Others:

Fast Food Toys
http://www.kathysfastfoodtoys.com/

"A Tribute to Female Action Figures"
http://www.darah.com/orig/

Great information and photos for dolls and action figures.
http://figure-archive.net/index.htm

Good lists of various toy lines.
http://furbyrocks.tripod.com/index.htm

Various dollhouse related toy guides.
http://mydreamdollhouse.com/

Photos of a large variety of 80s and 90s toys, from member Leonie!
http://www.flickr.com/photos/leoniesparnaay/sets/72157621687222741/

Tons of toys, just like the url depicts.
http://www.tons-of-toys.com/

On http://www.archive.org/ (credit to zuse),
Look up old versions of websites, such as:

http://galoob.com
http://kennerproducts.com
http://playmatestoys.com
http://swibco.com
http://trendmasters.com
http://empiretoys.com
http://grand-champions.com

Search for old eBay auctions, use concise key words.
http://www.worthpoint.com/

Wishbook, Sears, Mattel, and Toys-R-Us Catalogs
http://wishbookweb.com/
http://www.flickr.com/photos/wishbook/sets/

Hasbro Toy Instruction Manuals
http://www.hasbro.com/customer-service/toy-game-instructions.cfm?page=&per_page=50&order_by=L&current_page=6

~

I may accidentally post a link that has already been posted, sorry about that!
-Em

[BattySparkles]

Wow! Thanks for the My Pretty Mermaids link!

[EmBee]

You're welcome!  I loved my My Pretty Mermaid.  !

-Em

[EricaVee]

Weird that there's a MPM named Crystal Starr--wasn't that the name of the main Moondreamer?

[pikapal]

Yeah Hasbro likes to reuse the names, so does Mattel there were little pretties named Catra and Frosta.

[EdenEye]

This one is a really good Puppy in my Pocket website. Has info on other similar items as well. Its in English and Finnish.
http://vintage.talviuni.com/

[EmBee]

Wow excellent!!  Thank you SO much!   

It will be wonderful to look through all of them once again.

-Em

[MercurialMonster]

Besides Pony Market, another place for info on G2 MLPs is Rainbow Forest: http://gen2.aien-hime.com/
I like to hop back and forth between both sites for info when I am researching G2 ponies.

This site, http://www.etherella.com/ has a bit more info on the Euro/UK release ponies (in the Pony Scrapbook), as well as The Jem Encyclopaedia.   

Tabby's Toy Lists was a site I used to use for a few of the toys I collected, back before I found Ghost of the Doll:
http://furbyrocks.tripod.com/index.htm  (here's the main page of her site, which also has info on Fashion! Polly Pocket, and MLPs http://tabbymlp.tripod.com/)

Most of the other sites I use, or have used, are already listed (or I can't find them anymore).   Just thought I would add a few more, even though I am not sure the owners keep them up anymore.   I know some parts of the "newer" version of the Pony Scrapbook are dead, and I haven't been on the other two much recently to say where there might be dead pages or images, but they are still serviceable enough.

[EmBee]

Thank you MercurialMonster, I really really like some of those sites - they are gems!  I added in some of the links to the list.

Thanks a lot!
-Em

[Mitsy]

Sorry for bringing up an old thread but I also find the list of sites useful. However I have a teeny-weeny problem:

I don't know if it's the same thing but I'm wondering whether people have a list for finding toys at good prices. I know of a toy deals website as well as the usual comparison site.

Does anyone know of a good deals site or price comparison, but a dedicated one which is regularly updated, rather than Kelkoo and the likes?