stars near titles when creating giveaways

They are bundle games and will only count as contribution value up to a total of $30.

They are from bundles. You will not get contribution value for those games. The contrib value will cap at 30$ with bundle games.

To try and sum up a better answer than previous two: The star means the game was in an indie bundle (Humble Indie Bundle, Indie Royale, IndieGala etc) and if you give away only those kind of games you cannot get more than $30 contributor value total on your profile. If you give out both non-starred/non-bundle and starred/bundle you can get more contribution from the later if they are in good proportion.

Thanks for replies!