Bbc Radio 4 have any number of dramas in their back catalogue. One that I particularly enjoyed is Alan Plater’s Only a Matter of Time - available on the Internet archive, I find.
Then Orson Welles original War of the Worlds by the Mercury Theatre on the Air in 1938 is well worth a listen. That is available in several places around the Web.
Then, of course, there is Big Finish, who started off doing Doctor Who audios and have produced hundreds over the years - far more hours than there are of T V Doctor Who, classic and new - but they also produce a lot of other dramas, based on other properties and some completely original.
Overall their earlier ones are where the standout tales are, but they are fairly reliably entertaining throughout.
Also Beforeigners (2019, Norway), which kinda qualifies for all of these categories.