Where to find viral content to share on social media?

In your question,you have the answer too.Buzzfeed,stumbleuopn,digg, reddit and other similar kind of websites provide viral content due to large number users on these websites surf internet and find the best piece of content to share on social media to go viral.

It is a daunting task to find content but when you get the treasure trove of viral content then your problem would be solve.

Keep Surfing....

Virality is a formula that you need to evaluate. Even then, it can be pure luck.

Whilst sharing others content may provide you with a piece of viral pie at times, it's much better to create your own tantalizing content that everyone else shares and you get 100% credit for. At the end of the day, just like in affiliate networks, the only person you are truly helping the most, is the one at the top of the ladder. The one that started it all, The content creator. Get creative and be daring. Create your own unique content that others will share and make you the new viral sensation.

- Look at what's worked for other people before. Don't replicate it, be inspired by it. Think outside the box.
- Build relationships with the influencers so that when you make your awesome content you can tell them about it and they will share it. Easier to get the ball rolling that way.

you do realize you just asked a million dollar question yes?
if it were that easy to go "viral" , if there was an exact replica to go viral, everyone would do it.
some things are just magically lit on fire while others can't go any further than tits own original post.

Trending and Viral, by the way are two different things as well
nothing wrong with following whats trending
viral is a runaway lottery train

If you are looking for content that is already trending, simply check twitter for trending hashtags
this site can help you with that:
https://www.hashtags.org/trending-on-twitter

as far as creating your own viral campaign?
the best advice i could possibly offer is you have to be completely fearless and not afraid to offend in todays politically correct world... "mostly" anything viral is based on shock value, otherwise it's just like anything else.

best of luck