How to effectively get information about the collection from external API when there is only by-id-endpoint available?

What to do when you have a collection of elements, for example there's a 1000. And you need a detailed information about each of them from an external API, but there's a catch.

That API only allows to get detailed information one-by-one. So this is a painfully slow process.

How do you manage that situation? Are there any workarounds in .NET? Or do I need to speak to the developers of that API? Haha