You can search GitHub users by email. You need to use Google Spreadsheet and Google Apps Script.

1. Open https://docs.google.com/spreadsheets/d/1BvsAigG9ktvXbvLa9ScY656rNAkap7cgS2D_D0vlFwg/copy
2. Make a copy
3. Insert emails which you want to search on GitHub
4. Select Tools > Script editor
5. Run main function and review permissions
6. Set Time-driven trigger (Every minute)
7. Wait for the values to be entered
8. Delete the trigger set in step 6

You need to understand the limitations below.

• Google Apps Script (URL Fetch calls)
• GitHub API (Search)