If KR did crossovers outside of tokusatsu....
 

What show would you all want the kamen riders to join in?

Like remember when Marvel heroes teamed up with Phineas and Ferb?

Hmm not sure, although I would love to see some armor and weapons from Kamen Rider in Monster Hunter. The more I think a about it, the kooler it sounds xD

Decade X Doctor Who!

Both are passing through helpers that get into some crazy shenanigans.

Kamen Rider in Tiger & Bunny.

Drive X The Flash, I watch both shows right now and my Head canon is the Slowdown was caused by the giant reactor from the Flash. Shinnosuke and Barry would be so much fun.

Kamen Rider Ryuki x The Hunger Games

Kamen rider Gaim x Highlander
Kamen rider Wizard x Doctor Strange

Decade x Ben 10 (Had this idea years ago)

Matrix is about to post.
Gee, I wonder what his idea would be.
Clearly it'd be Kabuto x Iron Man.

But seriously, give me SD Riders x My Little Pony.

Kamen Rider x Godzilla: Battle of Titans