TT2020Base by ctrlcctrlv is a plain sans-serif that comes out of an open source project on GitHub. The main file is the Regular, and the family has two files, so there is a second weight or style sitting next to the base when a layout needs a change of tone. Since the project is public, you can follow its history and file an issue the same way you would with any repository you depend on.

Latin coverage reaches past 297 languages, so a Polish product page or a Turkish onboarding flow keeps its diacritics intact. Coverage that wide also means fewer fallback fonts in a stylesheet, since one family can handle a site that publishes in several languages. I would reach for it on developer tool landing pages, open source documentation sites, multilingual annual reports that mix languages in one spread, and indie game menu screens that want a quiet UI face. The Regular carries body copy at reading sizes, and the second file in the family gives you emphasis without loading a different typeface.

Pair it with a serif for headlines if you want more character above the fold; on its own it reads as a workhorse that stays out of the way. TT2020Base is under the Open Font License, so you can use it in personal and commercial work, and the files download straight from this page.