Sometimes text fonts/polices can be expensive to buy, or you have to pay extra money for commercial uses,

A lot of people search for fonts by googling it or by searching in websites like Dafont but those fonts aren't necessarily free for all uses also they are not - in my  opinion - the most original ones

Also you might like a font but can't modify it since it's not open, that's why open-source fonts are the best because you can actually modify them and fit them to your needs

Here is where you can find the best and most original open and free fonts for your projects/works etc..

Open Foundry

Open Foundry
A new platform for open-source fonts in a noise-free environment, to highlight their beauty, extend functionality and encourage further exploration.

Open foundry is a curated list of free and original open source fonts you can use for all your needs, the website actually let you try these fonts on the website itself before downloading them

Use & Modify

Use & Modify is a selection of beautiful, classy, punk, professional, incomplete, weird typefaces. Open source licenses make them free to use and modify.

Are.na open source typefaces

Are.na / open source typefaces
Are.na is a social platform for creative and collaborative research.

It's a list on the are.na social network where you can find a list of open source fonts, there is a lot of fonts there and even other websites when you can find free ones

Fontsquirrel (not necessarily open-source)

Free Fonts! Legit Free & Quality | Font Squirrel
Handpicked free fonts for graphic designers with commercial-use licenses.

Free commercial-use fonts website

Google fonts

Google Fonts
Making the web more beautiful, fast, and open through great typography

Free and open-source fonts hosted by Google so you can use on your website by adding simple snippets in your css/html code — you can also download them :)