Airdrop is the process by which a new project offers free coins and tokens often in exchange for minor social media Tasks, like joining a telegram group or following the projects twitter account, helping in getting the product seen by others as well as getting them in direct contact with those who share interest, most airdrops will distribute coins to the wallet address you've given within a few weeks of your initial sign up or end of ICO so It's basically a win-win for both.
Bounty is an incentive reward program to entice people to learn about the company and help spread the word, by providing some free tokens in exchange for specific tasks such as creating content material for project, translating them into different languages,writing articles, reviews and creating Video demo,
providing Graphic designs for there websites.
Will update this topic daily or Weekly with Airdrop and Bounty Programs of existing and upcoming projects
Note : Please do your own research before investing in any project