Pick a topic and read through its Chinese words, each with an English translation and part of speech. 22 topics, free, no sign-up. Pinyin included, so you can say each word. The app holds the full packs.
Watch Your Language puts Chinese words like these in a widget on your iPhone Lock Screen and on your Apple Watch face. You see a handful of them every time you check the time, and the app schedules the repeats so the words you keep forgetting come back more often than the ones you already know.
You can add your own words too — from a photo, a page of notes or a spreadsheet.