Cornell Lab has some great resources. I wanted to share this Shorebirds Identification Chart. Two pages! 

"From plovers to peeps and beyond, become familiar with the diversity of shorebirds with this free downloadable guide! Paying attention to shape, size, and behavior goes a long way to identifying shorebirds. This helpful shorebird ID guide has full-color photos, ID tips, and a size reference chart for use at home or out in the field. You can download, print out, and bring this guide with you!" 

Shorebirds Identification Chart