@amyb
I can give you first hand knowledge .
It's going to take a little prep work to approach a dealer.
Make a list. Doll Size Any identifying marks Maker Approx Year
Box? A spreadsheet would be most beneficial.
This is very important information to speak to anyone.
If you don't want to do the work, your return will reflect that.
If you have old Barbie dolls, Madam Alexander etc. those prices are be researched with books. There are actual price books that you can use as a reference. Also, you can check the back of the doll, neck, back and butt have the markings if they are there.
If you just want to get rid of them all, there are collectible stores that will possibly buy your entire collection.
If you want to sell them on your own, you need the above information to advertise them to the best of your ability.
You can also research doll dealers in the US but note the dealer needs to make money too and it's usually 40/60. Also, don't let the dealer pick what they want and give back the rest, sell them as a "lot".
The 80's was a hot market for dolls, not so much anymore but there still is collectors out there, it always comes back, just don't know when.