This app was mentioned in 10 comments, with an average of 2.00 upvotes
Clozemaster is my current favourite, it has a great free website, as well as an app (both for Android and Apple).
You're basically learning words in the context of sentences. I've actually managed to pick up on more grammar there than I have on Duolingo because of the overall method.
Maybe not the best, but Clozemaster is a quick way to practice vocabulary / phrases.
Another great app for language learning is Clozemaster. Together with AnkiDroid and Duolingo, they all complement each other.
If you're okay with apps, there's Clozemaster. It's more of an SRS, but maybe you can find the source for the sentences.
Clozemaster
https://play.google.com/store/apps/details?id=com.clozemaster.v2
They show you sentences with a word missing and you fill it in or select the missing word from a word box.