Most of the 'Long Medley' from Abbey Road is stuff from Rishikesh - mostly the Lennon numbers.
There's also, from my rather mild forays into lennon bootlegs, a large amount of recycling - Hey Bulldog's chorus was originally something called 'She Can Talk To Me'
http://www.youtube.com/watch?v=YWqW39eGSd0&feature=PlayList&p=E389B5A656ACC04B&playnext=1&playnext_from=PL&index=5and the bridge of 'Real Love' originated here
http://www.youtube.com/watch?v=SPoLDiGeLoYAlso, What Goes On from Rubber Soul apparently dated back from 1963.
I would also be willing to bet that rather a lot of Plastic Ono Band/Imagine had been written during his Beatles days, judging by the lack of material he had on the last two records. 'Look At Me' was another Rishikish one, so he says.