@Dmitry Maslennikov - I did check and if you are a licensed customer you can download 2021.2 InterSystems IRIS For Health CE from the WRC Software Distributions page: https://wrc.intersystems.com/wrc/coDistCD.csp
But I'll still push to figure out why it's missing from containers.InterSystems.com ....

Great news Mike!  Thanks for your work to make our Preview Software more widely available :)

As a further point on this topic, Customers can continue to get Preview Kits via the WRC Downloads if they wish to do it as they have in the past.  This enhancement to Evaluation now makes it possible for the first time for Prospects to access our Preview kits.  

@Yuri Marx Pereira Gomes - there is one thing that I don't see on this list (probably because it is a newer resource), but should probably be the first thing listed in the article:

https://gettingstarted.intersystems.com/

InterSystems IRIS Sandbox with browser-based IDE for walking through guided tutorials on a number of topics.  If someone wants to be hands-on in minutes and ramp up their learning from there, this is probably the place to start!!