Among the popular IEO, Harmony is one. They have been running a bounty program even before the binance partnership and with it getting the lauchpad of binance, the attraction towards it's bounty has highly increased. Though I believe token bounties are a better earning, I prefer quick cash for my work.
I think trading has faster and more results, even though it has a greater risk than bounties, but if the project has good progress, I'm sure there will be many participants in the bounties who will make the reward which received by each participant will be very small