Lorcan was in my office looking at Identity timelines recently. It is easy to find people whose publications are more common now than they used to be, probably because of the huge growth in publication in general, coupled with an increase in higher education (or third level education as Lorcan put it). It's a bit harder to think of someone that is no longer popular. So I wrote a little program to look for us.
There are many thousands of people with more publications before 1800 than after, and even around a 150 people who have at least 100 manifestations in WorldCat and a publication history that shows more published in the 17th than the 18th, more in the 18th than the 19th and more in the 19th than the 20th century. Here are a few examples:
Gilbert Burnet, a Scottish theologian and historian
Henry Hammond, an English clergyman
John Tillotson, an English Archbishop
Charles Drelincourt, a French Protestant
Philippe Labbe, a French Jesuit
Well, almost forgotten. Most of the 150 have Wikipedia articles about them.