Eugene Obrezkov made it really cool: 4 languages, 50 solved challenges (at the moment of writing), the detailed Russian explanation on Telegram (https://t.me/wild_wild_web)

I really like that there are resources like that. It improves the TypeScript knowledge and make people dig into details

These problems and solutions are quite well put together, and I haven’t seen another resource like it. There’s a ton out there about writing Typescript, but not nearly as much about writing types, especially higher order types.

In a slightly different vein, I love this site for helping me study and understand deeper practical implications and corner cases of type system designs: https://counterexamples.org/

About other resources, I also write about TypeScript solution here – https://blog.beraliv.dev/2021-04-04-type-challenges

I didn't mean to complete with Eugene, just wanted to spread my knowledge in TypeScript and also explore the possibilities of TypeScript

Very nice! I didn't find this earlier, thanks for sharing.

Agreed, with all the explanations in there it's an excellent source to learn about “type arithmetic” in TypeScript.