A lot of the euphemisms for swearwords were created in the US, I believe. Perhaps something about the puritanical movements being stronger there in the past (compared to the UK)? Don't know, I am only supposing. But new ones are nowadays being created in the UK, and one of the most prolific creators of such is the British author Terry Pratchett (whose writings just crack me up). Perhaps because he started writing for children, but wanted his books to be enjoyed by grownups as well, he has developed a nice line in innocent swearing. My favourite is:

"Millenium hand and shrimp!"