One could apply several methods of promoting, selling large numbers of domains such as: running a one-pager at that domain, promoting its value; or parking; or even create a web site with listed domains for sale; or promoting at domain sales forums; or offline ads listing parts of the portfolio etc.
Which methods work for you, do you try different things and what's your experience there?
Personally, all the domains I've put a one page 'for sale' page on haven't attracted even a whiff of interest. Some of the sites I've actually developed and added content to (not with the intent of selling) have attracted offers though.
But I'm not in the 'mass domain selling' business, so you might not have time to try and develop each one.
If you have lots of domains the same logic applies. The good ones will attract attention, no matter what you do. Bona fide parties will deal with you no matter how you present them: All on 1 page, individual splash pages, no page at all but a cryptic note in the WhoIs records about "for sale".
If you're really lucky or skilled you get to recover your investment on a few gems and then decide what to do with the rest.
You can always unload so-so names at the various domain forums. There's often some hopeful soul who thinks they'll get lucky with your trailings.
Putting my own for sale notice on sites has never attracted any interest. Building a website listing all my domains, with or without prices, has had no interest. But that could just be my poor marketing.
I've had some success selling higher-value domain names while they are parked at one of the major selling sites (the German-based one), but even there 90% of offers go nowhere, seems to have gone downhill recently, and it's hardly volume stuff (too few domains are worth paying the high commission charges for).
I've also cleared some domains through the bargain "bazaar" at another major domain selling site. Could be some good volume there if you worked at it (many sales a day possible). But with the tiny transaction sizes it's a lot of work for very little, like ebaying low-value stuff.
Basically, 99% of domains are worthless (nobody will pay more than the registration costs) so it's hard to get any sort of volume going. What's worse is the majority of buyers are clueless so it's really support intensive.
I'm finding it cheaper really to let the more average domains expire than waste time trying to sell them.