I only knew a few of the 'commonly said' ones :\
Maybe the point was to be creative and come up with something funny though
- It's always darkest before the dawn
- No news is good news
- You can't teach an old dog new tricks
- Love all, trust a few
- The pen is mightier than the sword
- Where there's smoke there's weed fire
- A penny saved is a penny earned
- Two's company, three's a crowd/party
- Better late then never