Lernen Sie Russland kennen! (Valeria M. Nechaeva): book with authentic Russian readings and vocab definitions in the footnotes exploring Russia after the end of the USSR (but you have to know German)
Chinese
Hanzi Writer Demo: visualize correct stroke order of Chinese characters online
Chinese Grammar Wiki: explanations of Chinese grammar topics, sorted by A/B/C or by HSK levels
Lazy Chinese: comprehensible input in Mandarin, sorted by proficiency level and with interactive transcripts (both free and premium content)
PunMemeCN: a GitHub repo of Chinese memes, together with structured data providing an explanation of each pun meme and example chat contexts in which it would be used