Hello everyone!

Currently I'm working on my menus and HUD stuff for the game and I was just wondering, what commercially free to use fonts could you recommend? I'm using Unity and default (Arial) font seems off somehow. I've seen lots of amateurish assets flips in Google Play store and one thing that catches my eyes the most are these ugly fonts which kind of ruin everything. I don't know if anyone feels the same way, but for me a good font seems to be important.

Is there are a preferred type of font (for example monospaced, etc) used in games? 

Also sorry, I haven't done much research on the subject and maybe it's too early to ask on forums, but I know you guys always have some awesome suggestions. So feel free to share them

Thanks in advance 

P.S. I'm looking for something simplistic, and not too flashy.

Thanks, guys, I'll have a look into these

I think there's a certain amount of meaning and mood behind a choice in typography, so it's difficult to make any suggestion without knowing more about what your game is and what it looks like.
You're not only looking for something thats "simplistic, and not too flashy" but also something that will look good together with the other graphics elements you have on screen.

The font is also something that has a recognition value for your product. So, as @Kryzon said, you need something that's unique enough, readable (not everybody is young and healthy) and fits your game.
Depending on project scope you might even need a complentary one to use in documents and websites.

Be careful with some of those "free" fonts on the internet. Some are only free for local install on one computer or for use in print / digital publishing of documents, not apps or games.
Always read the terms carefully. My advice is, download from the creators website if possible and if in doubt, send him/her an email to get permission (maybe for a small donation or credits).

FontSquirrel is a website specialised in royalty free, commercial-use \ permissive fonts.
https://www.fontsquirrel.com/faq