#1 Brock Lesnar vs Batista
It's so unfortunate that this feud never happened and, is considered one of the biggest missed opportunities made by the company. Both the wrestlers joined WWE in 2002 at the same time and, were a part of 'Ohio Valley Wrestling' which was WWE's developmental territory in the year 2000.
The two superstars did battle when they were a rookie in OVW which ended up with Batista getting the win over "the Beast Incarnate". But, things have changed since then. Brock Lesnar is the most dominant superstar in the WWE today.
On the other hand, Batista returned to the WWE in 2014 and, went on to win the Royal Rumble the same year but, unfortunately, the audience did not care about his potential feud with Randy Orton as they expected Bryan to win the Royal Rumble match. "The Animal" was vehemently booed and, tapped out to Bryan in a phenomenal encounter at WrestleMania 30. Dave quit WWE later in 2015 and, went back to Hollywood.
But, it has been rumoured that Batista might be looking for a potential comeback to the squared circle and, it could be the correct time for WWE to book this fascinating encounter. Expect Brock Lesnar & Batista to go toe to toe with each other in this remarkable feud.