1. Anker Astro E1 5200mAh Candy bar-Sized Ultra Compact Portable Charger (External Battery Power Bank) with High-Speed Charging PowerIQ Technology (Black) (Click Link to Check Price on Amazon)
Editor's Rating : 9.4 out of 10
The Anker Advantage: Join the 10 million+ powered by our leading technology.Exclusive PowerIQ Technology: Detects your device to deliver its fastest possible charge speed up to 2 amps (four times faster than a computer USB port). Does not support Qualcomm Quick Charge

2. Anker PowerCore+ mini, 3350mAh Lipstick-Sized Portable Charger (3rd Generation, Premium Aluminum Power Bank), One of the Most Compact External Batteries (Click Link to Check Price on Amazon)
Editor's Rating : 8.9 out of 10
The Anker Advantage: Join the 10 million+ powered by our leading technology.High-speed Charging Technology: PowerIQ detects your device to deliver its fastest possible charge speed up to 1 amp.

3. 16000mAh Most Compact Portable Charger External Battery Power Bank High-Speed Charging powerful 3.1A Output for iPhone and Samsung Galaxy ExpertPower Alpha (Click Link to Check Price on Amazon)
Editor's Rating : 9.3 out of 10
16000mAh rechargeable capacity guarantees you'll never be without your smartphone or tablet due to a dead battery.Lightning-quick output speed (5V / 3.1A total) through dual USB ports (5V / 2.1A and 5V / 1A) allow for simultaneous charging of your iPad, iPhone, Android, and more at high speed

4. EasyAcc 20000mAh Power Bank (4A Dual-Input Fastest Charge 4.8A Smart Output) External Battery Pack Charger Portable Charger for Android iPhone Samsung HTC - Black and Orange (Click Link to Check Price on Amazon)
Editor's Rating : 8.8 out of 10
20000mAh High Capacity: Charge an iPhone 7 6 times, a Samsung S7 5 times or an iPad Mini 3 2 times.Life Saver: Unique 4A Dual ports input (charger adapter not included), can be superfast recharged in 6 hours, reduce the recharging time up to 50% than usual 20000mah battery.

5. Portable battery, JETech 5,000mAh 2-Output Portable External Power Bank Battery Charger Pack for iPhone 6/5/4, iPad, iPod, Samsung Devices, Smart Phones, Tablet PCs (Blue) - 0758 (Click Link to Check Price on Amazon)
Editor's Rating : 9.2 out of 10
5,000mAh capacity with TWO USB outputs: one with built-in micro USB cable for Android device, the other 5V 2.1A. On/off button to stop/resume charging, 4 LED indicators displaying battery percentage and charging status. Grade A Li-ion polymer cell and premium microchips create high-quality portable chargerBuilt-in flash light. Comfortable and luxury touchï¼›Stylish, lightweight design fits easily into any pocket or bag