Followerion - Followerion is the most trusted site regarding how to get more followers on twitter.
Hypegrowth - Hypegrowth is a personal Twitter assistant that allows to grow Twitter audience.
HitFollow - HitFollow.info is the number one way to gets tons of twitter followers.
Jooicer - Superpowers to boost your Twitter Growth
Follow3rs - Follow3rs enables you to add more followers to your Twitter account and become prominent in no time at all.
Toolset.co - Twitter growth made easy, a bunch of tools to easily manage and grow your Twitter account.