3 (in Japanese)
One of the easiest ways is to use the aforementioned Gravecrawler
Dinowrestler Pankratops X EARTH Level 7 [ Dinosaur / Effect ] ATK 2600 DEF 0 If your opponent controls more monsters than you do, you can Special Summon this card (from your hand)
$ 0 Ability Ultra Road Once during your turn (before your attack), you may switch your Active Pokmon with one of your Benched Pokmon

Other searchers of the "Predap"/"Predaplant" archetype with useful additional effects include "Predaplant Sarraceniant" (which can Special Summon itself to block an opponent's monster's attack, can destroy monsters that battle it and searches a "Predap" card when it destroyed or sent to the GY by card effect), "Predaplant Ambulomelides" (adds any "Predap" Spell/Trap or 1 "Predaplant" monster from the Deck, GY or face-up Extra Deck upon Fusion Summon, and can Tribute any monster on the field with a Predator Counter to Special Summon any "Predaplant" monster from the Deck), "Predaplant Byblisp" (searches any "Predaplant" monster when sent to the GY), "Predaplant Longinephila" (searches a "Predap" card on Summon and is a potent one-card combo by itself), "Predapractice" (Special Summons a "Predaplant" monster from your hand and searches any other "Predap" card), and "Predaplanet" (which searches any other "Predap" card if a monster with a Predator Counter leaves the field)

Its still slow, but it works a lot like a Rampant Growth if you can get it into play on turn 1