Well, nobody actually uses dPolls, there's precisely 8 polls within last month. As far as I know, Peakd offers a better polling tool nowadays.
HiveTasks is just adapted, the original app runs on Steem and was developed by @steemchiller. Trello is a Kanban list-making app, Steemworld/HiveTasks are a universal multi-purpose tools for account governance. I am not sure if all the funcionalities of HiveTasks actually work, since they were originally intended for Steem.
If you wanted to write about Hive dapps, here's a list: https://dappradar.com/rankings/protocol/hive