I've sent a transaction with Electrum, but accidentally included too little fee. What can I do to speed up the transaction's confirmation or to replace it?

^{This is a complementary question to Why is my transaction not getting confirmed and what can I do about it? which answers the question's broader implications and proposes mitigation mostly focused on Bitcoin Core.}

I've sent a transaction with Electrum, but accidentally included too little fee. What can I do to speed up the transaction's confirmation or to replace it?

^{This is a complementary question to Why is my transaction not getting confirmed and what can I do about it? which answers the question's broader implications and proposes mitigation mostly focused on Bitcoin Core.}