The two references to fonts.googleapis.com use fonts which exist on wmflabs's FontCDN and can thus be substituted accordingly:
The other fonts can and should be removed absent indications that they are free/open-source and thus readily hostable on Wikimedia servers. Some references to these fonts in other stylesheets include, on a cursory search, https://bn.wikibooks.org/wiki/ব্যবহারকারী:Aishik_Rehman/common.css and https://bn.wikibooks.org/wiki/মিডিয়াউইকি:Perbook/Wikijunior:Countries_A-Z.css.
Disabled these by default too: https://bn.wikibooks.org/w/index.php?title=%E0%A6%AE%E0%A6%BF%E0%A6%A1%E0%A6%BF%E0%A6%AF%E0%A6%BC%E0%A6%BE%E0%A6%89%E0%A6%87%E0%A6%95%E0%A6%BF:Common.css&diff=prev&oldid=43917 Leaving this task open for any possible follow-ups.
Toolforge is not hosted on the production cluster which means that resources can't be loaded from there without user consent like any other third-party site.