Switch Twitter Accounts in Safari? There's add-ons for Firefox to do this, switching twitter accounts without having to sign-in 3-5 times a day is really time saving if you have more than 2 accounts, CookieSwap do the job, is there any possible extension can do the job for safari?
There is no add-ons on Safari who is doing that.

Chrome : 
https://chrome.google.com/webstore/detail/swap-my-cookies/dffhipnliikkblkhpjapbecpmoilcama

Mozilla :
https://addons.mozilla.org/fr/firefox/addon/cookieswap/

By the way, I think you have to post your wish here : https://www.reddit.com/r/SomebodyMakeThis/