Zinc

https://zinc.it

Zingtree

https://zingtree.com

Yandex

https://yandex.ru

Yangaroo

https://yangaroo.com

Yala

https://yalabot.com

Yalla

https://yallahq.com

Yammer

https://yammer.com

Xmind

https://xmind.net

xsellco

https://xsellco.com

XWiki

https://xwiki.org