Not sure if other banks do the same but mine HSBC offer a stamp to use instead having to sign.
The Passport office have an option where you don’t have to sign for your passport renewal, you will need a letter confirming why you can not sign.
Postal votes your local council can arrange for those with postal votes to not have to sign when they vote. They will email or sent you a form which you get someone to filling for you and return
Johan