Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.
ViralSweep - Grow your fans and increase sales with sweepstakes and giveaways.
TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
Retweet Pick - Retweet Pick is a random name generator for Twitter giveaways via generating a winning name from the list.
HootSuite - Enhance your social media management with Hootsuite, the leading social media dashboard. Manage multiple networks and profiles and measure your campaign results.
Retweet Picker - Retweet Picker is an online tool that is helping you to select the random winner from Twitter for the giveaways.