I really like your idea and I hope that you find a good organisation. I am not sure if I can help you but suggest trying these:
Caritas.
http://web.caritas.ch/page2.php?pid=1 and
http://www.caritas-aargau.ch/
There is a shop near you in Aarau but I don't know if they will take toys.
Caritas Boutique
Metzgergasse 20
5000 Aarau
Tel: 062-824 15 20
There used to be a collection around Christmas in Zurich but I haven't heard anything for this year yet.
Then there is
2xWeihnachten (Christmas twice) but they collect mostly toiletries
https://www.2xweihnachten.ch/Default.aspx?lang=4 Heilsarmee (Salvation Army) might be interested in some toys as well. Maybe contact them at their headoffice in Bern
http://www.heilsarmee.ch/
If you're not lucky maybe contact your Gemeinde they might be know of families in need? Maybe you could bring it to the Gemeinde and they could let the family know that they could pick up the toys (if they don't want to give you the addresses) or ask a Crèche or Kindergarten if they could use toys.