Oooh, let's see...

@steembasicincome - I love that I can buy shares to help accounts on their way with regular upvotes and I gain shares myself which helps to build my account so I can continue to support others.
@pifc - (Pay it Forward Contest) gains attention for lower level users and you can be any level to submit curation posts.
@comedyopenmic - I don't post often for this comp, but I've found them a lovely community and it's great for brightening up your day. Chances are good that you will gain upvotes from COM itself and the current judges, as long as you're posting decent content. COMers are also encouraged to upvote other entries, so posts circulate well. Then of course there's the chance of a prize of Steem. All this, just for posting.

These are some of my favourites. I'm about to look a bit more into @minnowbuilder, from the same account that does @pifc. Similar to @steembasicincome, but with a redfish sponsorship side to it.