@burnout426 After this conversation, I have explored this add-on extension to open the URLs in bulk and it works well. It is my suggestion for anyone who is worried about the bulk URL opener on Opera he must explore this https://addons.opera.com/en/extensions/details/bulk-url-opener/ .
If there is any other better option on Opera, drop it here
Thanks, @burnout426, for your consideration.

Incredible Extension to use on the Opera.

@burnout426 Right, but here is a thing at last. If i want to open my this site of gratuity in 100 tabs at once then how it is possible? In chrome i use the bulk url opener extensions to open it.

@burnout426 Right, I try it. Thanks

I Couldn't find any reliable answer until now.