Have 2 Books Plus Site - But Strategy

I was wondering if I could get a few perspectives from others on this.
Here is one of my situations.

I own the copyright to two books I wrote a long time ago but are now out of print.

I also own a very old domain name which comes up in the top ten.

So I have been studying the forum here, and learning that unique original content, a niche, and a relevant (preferably aged) domain name are key, And I have those things. But I am not sure the best way to bundle up these elements so that customers and affiliates get a good deal and I make a little honest money from what I have.

I actually have masses of content - some previously published, some not, in various niches, because I am an avid researcher and writer. But the above is the most pressing situation for me because I cannot work out whether in fact there is any value in it at all.
I am not expecting anyone to tell me what to do
But maybe someone from the outside, used to viewing content from an online perspective, may have something to say that could help.
Many thanks.
PS: I am not in search of big bucks. Just a few