If your beginning reader finds pages of mostly-text intimidating, try some of the below, which have lots of illustrations to break up the text.
Barkus by Patricia MacLachlan
Bunjitsu Bunny books by John Himmelman
Captain Awesome series by Stan Kirby
The Critter Club series by Callie Barkley
Dragon Masters series by Tracey West
Fergus and Zeke by Kate Messner
Haggis and Tank series by Jessica Young
Inspector Flytrap series by Tom Angleberger & Cece Bell (shelved under "Angleberger")
Judy Moody and Friends series by Megan McDonald
The Kingdom of Wrenly series by Jordan Quinn
Flat Stanley series by Jeff Brown
The Magic Finger by Roald Dahl
Mercy Watson series by Kate DiCamillo
My Father's Dragon by Ruth Stiles Gannett
Magic Tree House series by Mary Pope Osborne
The Littles by John Peterson
A-Z Mysteries series
The Boxcar Children series
Capital Mysteries series
Inspector Flytrap series
Nancy Clancy, Super Sleuth by Jane O'Connor
Nancy Drew and the Clue Crew series
Nate the Great series
Young Cam Jansen series
Books about everyday life--school, family, getting into scrapes, and more.
Anna Hibiscus series by Atinuke
The Critter Club series by Callie Barkley
Ivy and Bean series by Annie Barrows
Lola Levine series by Monica Brown
Amber Brown series by Paula Danziger
Judy Moody series by Megan McDonald
Stink series by Megan McDonald
Lulu series by Hilary McKay
Juana and Lucas by Juana Medina
Life of Ty series by Lauren Myracle
Clementine series by Sara Pennypacker
Dory Fantasmagory series by Abby Hanlon
Dragon Masters series by Tracey West
The Kingdom of Wrenly series by Jordan Quinn
The Last Firehawk series by Katrina Charman
Zoey and Sassafras series by Asia Citro
Mermaids to the Rescue series by Lisa Ann Scott
Unicorn Diaries series by Rebecca Elliot
Diary of an Ice Princess series by Christina Soontornvat