This is by no means an exhaustive list. I will add links as I go (and please let me know if you know of a good one to add).
Helen Dowland
How Do I Know if my Child is Gifted?
Minnesota Council for the Gifted and Talented
Checklist: Is your child gifted?
Renaissance Academy
Recognizing Giftedness in Young Children
NSW Association for Gifted and Talented Children Inc
Characteristics of gifted children
The Queensland Association for Gifted and Talented Children Inc.
Characteristics of Young Gifted Children
Education Queensland - The Learning Place
Understanding Giftedness · Definition and Characteristics
Department of Education and Training Western Australia - Gifted and Talented Education
COMMON BEHAVIOURAL CHARACTERISTICS OF GIFTED AND TALENTED STUDENTS