That is a great question. We don't have a "list" as such but should probably think about one
What you need to consider is whether your tours are going to be SOLD by web sites - or promoted (marketed) and you take the bookings directly.
For your kinds of tours much of the promotion will be advertising based - for example http://adnet-media.net/ may be a place to start. Other sources are of course Google and Microsoft advertising.
Hi Walaa,
have you considered 'Infohub' or 'Viator" for global online distribution? Infohub charges a commission and refers booking to you for handling. Viator charges higher commission.
regards,
Dave