Nutritionfacts.org seeks translators
Nutritionfacts.org is a webpage that gives information about the science of nutrition for free and seeks translators, currently for Spanish and German. https://nutritionfacts.org/volunteer/translators/
I reckon it is only for well advanced speakers and quite a commitment, but some of you might look for new challenges now that immersion is gone? It will definitely expand your vocabulary in science.
As a professional translator, please don't do this.
If you are doing it solely to practice your language or 'expand your vocab', you will certainly be delivering a sub-standard job and will be doing this charity a disservice. Translating a public-facing site is not something you can do well when you've just completed a Duo course. It requires proper training. Most good translators have passed a demanding professional qualification and have many years of experience learning their languages (often at university), living in countries where it is spoken, etc.
Even more important, professional translators are only allowed to translate INTO their native language (except in special cases e.g. someone who has lived in another country for decades and become completely fluent, and even then clients are often reluctant). Even the best German to English translators would not produce completely natural German when translating the other way around. If you translate this website into German or Spanish, as a mid-level German or Spanish speaker, you risk producing complete nonsense and making the website look really bad.
I know people miss immersion, but please just go and translate a wikipedia article or something that you find interesting in your own time, don't actually offer your services as a professional.
They already have lower requirements than a paid job (they only require 'fluency' in a language, no qualifications, no references, no samples, doesn't ask how many years of experience). I don't think it would occur to the organization that people who weren't even fluent would apply just so they could practice their own language skills - the website makes it clear they are looking for volunteers to help them, not looking to provide a free language-learning service.
They are an English speaking team, so how are they supposed to judge whether someone who applies is actually fluent, or is going a good job? They can't read the German or Spanish to check it. They are trusting that people who apply to this will actually be fluent. It is frankly dishonest if non-fluent people claim to be fluent just to get an opportunity to practice (as if you even need an opportunity, if you want to translate just pick something and translate it for your own enjoyment!)
I have volunteered my services for charities before, and I know many colleagues who have also done so. Yes it's hard to find good volunteers, but they are out there if they know how to reach them, and I'm pretty sure they'd rather wait for a good one to come along than have their website translated shoddily.