The faucets as the word says are "taps" from which drops of cryptocurrencies come out, by drops it is meant that the cryptocurrencies they release are very scarce. This does not mean that you cannot make it a source of income! There are some who accumulate points to click on banner ads or captcha and then redeem them for cryptocurrencies. Of course, the gains are minimal, but the volatility of cryptocurrencies and other factors could drive up the gains. The most famous Faucets around the web (but also the most profitable) are:

• FireFaucet, faucet that allows you to accumulate points with offers, PTC and through a daily bonus; points which will then be redeemed for the autoclaim of various cryptocurrencies.
• Autofaucet, faucet in development and continuously updated, has recently implemented the web and gui mining.
• FaucetCrypto, simple faucet with a bonus every 20 minutes and which has a maximum limit for withdrawing about 2200 coins (700 satoshi btc).
• Allcoins, historical faucet that in addition to all the functions of the aforementioned faucets also has a section where there are games of chance with cryptocurrencies.