You can make your own list of all the stars closer than 3.6 pc using this interface to the Wooley catalog,
Go to this site:
and type "> 250" into the "Parallax" box, then click on "Search". That will give you a list of all the stars with
a parallax greater than 250 milliarcseconds, which means a distance less than 4 parsecs. This particular
catalog contains 33 such stars.
How many have been searched for planets? I'm afraid you'll have to do quite a bit of work to find out.
There are many different searches, some using transits, some using radial velocity. I don't know of
a single source which gathers together the information on the stars in each search, so you'd
have to go to the technical papers for each search and figure out which of these 33 stars fall
into the search area and satisfy all the necessary parameters.