I thought I'd just go ahead and answer today's prompt here. The blockchain tool I use the most is steemworld.org by steemchiller. I really like the UI and that it pulls in a lot of information via tabs into one window. I use it mainly to see what I'm doing, but it does come in handy if I'm looking for info about anyone else.
There are other tools that I will access but I don't use any of them nearly as much.