I've made a number of steem browser extensions over the years, some of them useful, some of them not so useful. But the one that is most useful and the one that I use the most is Steem VP.
It's a simple Chrome extension that tells you your current steem voting power, and a sliding scale to tell you the amount your vote is worth at different power levels. Really handy to keep track of your voting power so as not to deplete it too much while you are curating the blockchain.
It's available at the Chrome webstore - https://chrome.google.com/webstore/detail/steem-vp/imiphocgbfhmelcaeifmaalbpddeohpg