From the Wikipedia page 
Ricardians are people interested in altering the posthumous reputation of Richard III, King of England (reigned 1483–1485). Richard III has long been portrayed unfavorably, most notably in William Shakespeare's play Richard III (Shakespeare play). In an effort to turn this around and paint such characterizations as politically motivated, Ricardian historians' work has produced editions of documents from Richard's reign, research, and articles which have contributed to scholarship of England in the 1480s.
Ricardian historiography includes works by Horace Walpole and Sir George Buck. Modern historians such as Charles Ross and Michael Hicks, who write relatively favourably about Richard III, may broadly be referred to as Ricardians. Ricardian fiction includes Josephine Tey's The Daughter of Time and Sharon Kay Penman's The Sunne in Splendour.
The three most notable societies of Ricardians are: