CPU mining (is still alive!)

Proof of work mining requires computational power. There are ASIC miners, which are very tightly specialized in one algorithm, there are GPU miners which are very flexible and capable in many algos, there is even HDD mining. However, CPU mining is the most universal type of mining. Here are some of the most popular CPU minable methods:

1. JSEcoin - CPU only, web minable coin via browser.

A CPU only, web minable coin

You can mine it via JSEcoin's website. No special miner or knowledge required. I recommend instead of a new tab, opening a separate browser window for best results. It is very light miner and  you will not notice it while using your computer. Just press "start mining" and it will adjust automatically according to your use. You can also mine at your work computer ;) .  
If you own websites, you can integrate the miner in them. Your visitors will be asked if they wish to contribute to your website by mining JSEcoins for it. That way, without hanging ugly banners all over it, you can monetize your content.

2. uPlexa - the IoT coin

Mine with IoT

There are 8.4 billion IoT devices around the world. more than 50% of the time are not used for anything. Since they are spread all over the world already, mining vua IoT devices will create the most decentralized network ever. Combining IoT hashrate of billions of devices will create a massive computational power for transactions.It uses it's own modified version of the most secure protocol so far: Cryptonight. It is currently CPU only minable and with a low difficulty. To see the latest updates (daily!) I suggest that you join their chatty uPlexa's Discord. Alternatively, you can buy some on Stex, while the price is still affordable.

3. Coin Imp - Monero CPU mining via browser.

web mine Monero and Webchain

Just start your browser, login and push start mining Monero. Coins will be payed out to your Monero address once they reach 0.1 Monero. You can also CPU mine Webchain coin. For best results check your processor's L3 cache and divide that number by two. This will give you the number of cores you can use for optimal Monero mining. The CoinImp website also allows you to lower your CPU usage by as much as you like. This will allow you to use your computer as you wish while mining. You can also mine from your computer at work as it does not require any software download.