Percy Jackson and the Olympians series
by Rick Riordan
First book: The Lightning Thief

Young Bond series
by Charlie Higson
First book: Silverfin

Pendragon series
by D. J. MacHale
First book: The Merchant of Death
 

The Gatekeepers series
by Anthony Horowitz
First book: Raven's Gate

Note: Series link does
not include Raven's Gate

The Saga of Darren Shan  series
by Darren Shan
First book: Cirque du Freak

Maximum Ride series
by James Patterson
First book: Maximum Ride:
the Angel Experiment

Naruto series
by Masashi Kishimoto
First book: Tests of the Ninja

Note: This is an anime series

Code Orange
by Caroline B. Cooney

Acceleration
by Graham McNamee

The Supernaturalist
by Eoin Colfer