Baby sleeping bags for a second born child when they were a month old - like we'd not been using anything for them to sleep in for four weeks. Or didn't have any from our firstborn. Thing is, the same person gave us so many that we ended up with 16. And neither child would even use them.
A gorgeous expensive Christmas onesie in a newborn size for a baby due in January. Was given to me in October too so not like they got it in the sales or anything.
Dungarees for any child under 6 months.
Secondhand things bought from charity shops - I actually LOVE secondhand, but giving a new mother dirty, broken things with the instructions to 'give them a wash' is akin to a hate crime.
A secondhand book with dried snot on it.
A merino wool blanket that I accidentally felted into a tiny square 
The same book three times - from the same person.
Suede shoes for a newborn.
Jersey slings - I was gifted two and my child wouldn't use it.
A pink flouncy dress so hideous that it's like it was designed by someone trying to draw Bo Peep during a round of Pictionary. Crackly, pink, stiff nylon, lace and ruffles with matching knickers. Bought during a heatwave in July and was expected to put her in it there and then.
Flamenco outfit for a newborn. A genuine one with tassels and stiff lace.
Unwrapped gifts + wrapping paper and the instructions to wrap them first before giving them to the baby 