Not Updated For Current Season
These are some builds I plan on running in rated games eventually on Singed.
Build one: This build is for heavy magic teams.
Build two: this is for heavy physical damage teams.
Build three: This is a balanced build for balanced teams.
Build four: this is an AP/Tank build that is a lot of fun.
As for the runes, I mostly just work with what I have you can pick and choose as you please.
Summoner abilities, I always go with Ghost paired with your ultimate NO ONE will escape you.
The other will depend on who you are up against, if they have a really heavy pushing team with a lot of carries then get Fortify, if they have a jungle get Clairvoyance, if you have a lot of mana users or plan on laning with a mana hungry Champion like yourself then choose Clarity, etc etc.
My go to spell other than Ghost is Clairvoyance I use this one probably 9 times out of 10 when it doesn't matter what I use. This spell is amazing for checking bushes since you have to true ranged ability but it's also good for checking Baron and at the very start of the match you can use it in the enemy base to see what builds they are going for and what items they start with as well as see who is going to which lane which can give everyone on your team a huge advantage as you can pick who will be best suited for each lane.
I'm sure there are better builds out there but I am always changing my builds up and am open to suggestions, these are just what I whipped up in about 20-30mins that seemed like they would work pretty well.