Couple hundred domains isn't little. Perhaps you can sell them all together as a bulk to some database like https://alldomainsdb.com/. They may be interested in acquiring them all, especially if they are old and have plenty of links, I can imagine they'll be quite interested. And you can ask for more money than from a natural person.
Selling the entire lot to a domain vendor is the quickest way out but you would get peanuts, also because with so many new extensions approved recently, nude domains are pretty worthless apart of premium .com. You may target industry-related players, though, for the most attractive ones in your portfolio: placing one or two for a few thousand dollars to the end user would extract some value from the otherwise inanimate dross.
This might be offtopic, but im selling domain called privacyzone.org. If you're intrested contact me through contact form: https://privacyzone.org/domain-for-sale/
My knowledge might be outdated but sedo.com used to be recommended for selling valuable domains before.
Hey, this doesn't answer your question but I had to ask.
I'm building a side-project, where users will be able to list their domains for sale. What do you think I should charge as the listing price?
I'd also suggest flippa.com, and put a holding page on each domain linking to the auction/advert page, or a contact form.
You should post a list here. I'm sure many of us could use a nice domain for a side project
You can use something like Flippa, but like all the big sites, they'll rob you with fees.
can you provide a txt file of the domains in the event us here want to make an offer on one?
Try: https://flippa.com/
Also, you can look up something called GoDaddy Marketplace/After Market or something.
Also, you could try (bulk) updating the whois info of all domains with text like: This Domain is for Sale