One thing I have noted many transcribers are confused by - often leaving blank or mis-transcribing - is the 19th century abbreviation for "etcetera". Unlike our modern "etc." you will often see "&c." Additionally - and rather oddly - on formal signatures you will often see in closing titles reduced to: "&c., &c., &c."
Of course in other languages translation and abbreviation can vary as well: German = "usw" -- Italian = "ecc".