9. Nicole Scherzinger
Following the tragic death of Simpsons regular Marcia Wallace last month, what better celebrity to have as a guest star on the show than the woman who has, in the past, claimed that she often uses the name "Edna Krabappel" to check-in to hotels (seriously, look it up!). Although The Simpsons will honour and have already honoured Marcia Wallace and Edna Krabappel's legacy with several nods to the actress and character in episodes of the show, it could be a cool additional nod to have Scherzinger appear on the show using Edna's name to check-in to a Springfield hotel. She could be overheard doing so by a regular character and, when questioned about why she does it, perhaps she could say something along the lines of "I met her once, she was a nice lady". Aside from such a nod, given Scherzinger's level of stardom and the numerous "Scherzingerisms" that she says on the X-Factor in the UK, she'd undoubtedly be a popular guest and having her telling Marge that she was "Schermazing" would be rather funny.