I read Nimphidia for the first time last month, & felt moved to re-read, enjoying it just as much the 2nd time around. Despite Tolkien's criticisms, his poem "Errantry" has something of a similar flavour.
Briggs's entry on Nimphidia is collected under the topic Diminutive Fairies, which gives a potted history of the development of the Small People in Elizabethan times. I also found a blog which gives a more detailed & informative review of Drayton