#8 John Morrison (never lost: 3-0)
John Morrison returned to WWE earlier this year. He wrestled at SummerSlam on three occasions during his initial run. At SummerSlam 2007, Morrison bested CM Punk to retain his ECW World title. Three years later, Morrison was a part of Team WWE that defeated The Nexus in the main event of SummerSlam 2010.
In 2011, Morrison teamed up with Rey Mysterio and Kofi Kingston, and the trio picked up a win over Alberto Del Rio, R-Truth, and The Miz.
#7 Rikishi (never won: 0-3)
Rikishi competed at WWE SummerSlam on three occasions, with each one being a multi-man match. Way back in 1993, Rikishi, Samu, and Bam Bam Bigelow lost a 6-Man Tag Team match to Tatanka and The Smoking Gunns. A year later, Samu and Rikishi lost a Tag Team match to Bam Bam Bigelow and Irwin R. Schyster, this time via DQ.
In 2000, Rikishi was an incredibly popular babyface, along with Brian Christopher and Scotty 2 Hotty. The trio, unfortunately, lost their SummerSlam encounter against Right To Censor that year.