For an overview of Czech grammar, use the freely available package of memorization cards Hub Cards.
The constantly updated file covers various areas of the language, contains grammar patterns, additional help and examples of use.
The cards can be downloaded in PDF or PNG format, printed and further distributed under the CC BY-NC-SA 4.0 licence.
If you have an idea to add to the database, suggestions for correction or a comment on the content, write to us at firstname.lastname@example.org.
Thanks to the H5P module we can create free interactive exercises for the Czech language in Moodle which are available on our website.
Exercises contain various activities, such as gap-fill exercises, wordsearch or crossword puzzles, and cover various grammatical phenomena of Czech. Larger tasks offer test kits that summarize more information.
No registration is required to access the tasks, the results are not stored anywhere and the exercises can be repeated as you like. The right solution is part of each of them.
An updated list can be found here: https://www.language-hub.org/course/view.php?id=558§ionid=2551.