This is a great idea!
I teach in Korea and I use some of the holiday flash cards from your set with my students, but since their holidays are so different I had to improvise some of my own which didn't match and the quality just wasn't the same.

My suggestions for new cards are:

Lunar New Year: could be represented with a moon and animals from lunar horiscope.

Chuseok: the biggest holiday in Korea, people visit their families and eat ddok (rice cake) (it is a lunar holiday as well)

Buddah's Birthday: lots of lotus lanters and visiting temples

Thanks for the great site!

i propose Eid_ul-Fitr and ramadhan for new card. the content can be mosque, crescent and star, hijab, ketupat/rice dumpling etc. we can also teach culture to them, religion and culture sumtimes they are connected.

What about 5 November, Bonfire night in UK.

I agree that it would be great to have a set of flashcards that are specific for Japanese holidays. The kids would have to explain each day and why each one is unique or special.

Outside of that... a Canada Day card would be pretty nifty for us Canadians on these boards.

Great job Mark!!