Cydia
is an open, decentralized platform that helps you to install software packages
hosted by the independent repositories, also called sources or repo. Cydia includes
many addons for Action Menu, Alkaline, Apps,Development, Bootlogo, BossPaper,
Color Keyboard, Control Center, Cyget, FontSwap, Notification Center, Siri,
Zepplin. Like wise you can customize your devices by installing tweaks, themes,
wallpaper, Widgets, Ringtones and many more.

There are many more Cydia sources/repo for iOS 10, iOS 9 and lower which I listed as a best 2017 Cydia sources/repo for jailbroken iPhone, iPad and iPod touch

You can check out in the list of Cydia sources
section of the cydia. By default, Cydia includes BigBoss Cydia/Telesphoreo,
ModMyi and ZodTTD & MacCiti which contains thousand of popular and useful
packages. You are free to add un-trusted third party sources but you have to
add at your own risk. So beside these Cydia’s default repos there are many more Cydia sources/repo for iOS 10, iOS 9 and lower which I listed as a best 2017 Cydia sources/repo for jailbroken iPhone, iPad and iPod touch which includes millions of tweaks, themes, Addons, Utilities, development &
much more.

Here are the Best 2017 Cydia Sources/Repos
for iOS 10, 9 and 8 JailBroken iDevices (iPhone, iPad & iPad touch)


Compatible with iOS 10, iOS 9 or lower.
BigBoss Repo
BigBoss
Repo is one of the largest repo in Cydia and is default repo which includes
paid as well for free tweaks, themes, apps, wallpaper, games, addons etc.
Source: http://apt.thebigboss.org/repofiles/cydia/
ModMyi Repo
ModMyi
is another default repo in Cydia which includes many more stuffs like BigBoss.
Source: http://apt.modmyi.com/
HackYouriPhone Repo
HackYouriPhone
is a third party cydia sources & is popular for hacking and craking. You
can add this repo at your own risk. It includes thousands of wallpapers,
Addons, Themes, Tweaks and many more useful stuffs.
Source: http://repo.hackyouriphone.org/
BiteYourApple Repo
BiteYourApple
is a also a third party cydia souces and popular source for apps &
themes.It also contains some bonus tweak which is not available in default
repos.
Source: http://repo.biteyourapple.net
Xarold Repo
Xarold
is also the best cydia sources which helps to modify your devices by installing
useful tweaks and useful tweaks which brings your device homescreen as well as
lockscreen a new look.
Source: http://repo.xarold.com/
Xsellize Repo
Xsellize
is third party Cydia sources and is famous for  various games  like Gameboy,
Racing Games, Sega, NES, and more. It also includes many useful tweaks, apps and themes.
Source: http://cydia.xsellize.com
SinfuliPhone Repo
Sources: http://sinfuliphonerepo.com


iPhoneCake Repo
Sources: http://cydia.iphonecake.com/


iHacks Repo
Sources: http://ihacksrepo.com


Insanelyi Repo 
Sources: http://repo.insanelyi.com

How
to add Cydia sources / repository on your jailbroken iPhone, iPad & iPod
Touch
Step
1.
Open up Cydia.
Step
2.
Go to Sources.
Step3.
On the upper right corner Tap Edit and then Add you favorite repo link

There are many more Cydia sources/repo for iOS 10, iOS 9 and lower which I listed as a best 2017 Cydia sources/repo for jailbroken iPhone, iPad and iPod touch
Step
4.
After you added a Cydia/APT URL, Tap Add Source.

That’s
it. You have successfully added a repo.
Now
you can install any tweak, themes and many more stuffs you like.