Just came across CryptoTab - a browser extension which allows you to mine cryptocurrencies through just your browser.
It is a browser extension with a separate feature management page. The extension uses a part of your CPU's processing power to mine Monero. You can set the amount of your processing power that you want to delegate. After you do that and mine the crypto, it would would be then converted to Bitcoin and would be paid back to you in BTC. You can withdraw this at any time you want.
Steps to mine crypto:
You can boost your earnings through their referral program.