They come back if you renew it... I hardly see a problem with not renewing for some reason and going back.
For those of you wondering why you are no longer able to play the games you got on your 30 day trial of plus here is an explanation
FREE GAMES ; Any game / DLC you get FREE with plus expires at the same time your plus membership expires. Meaning you will not be able to play these games unless you renew plus, or buy the game. if you go the way of reuping for plus - you can still play the games from your old membership - even if your membership expired - if you deleted the games because you were no longer able to play them - you can find them in your download list and redownload them
http://community.us.playstation.com/t5/PlayStation-General/Plus-Content-After-Expiration/td-p/36130821