Here's a list of the 14 Google AdWords ad formats and their share of impressions.
Strip out the text ad and you are left with 13 ad format sizes. Use the share of impressions as a relative percent to each other ad and you are left with a clear picture of which ad size is served the most often.
We recommend starting a display or remarketing campaign with the top 6 formats:
Leader board (728 x 90)
Inline Rectangle (300 x 250)
Banner (468 x 60)
Wide Skyscraper (160 x 600)
Large Rectangle (336 x 280)
Mobile Leaderboard (320 x 50)
Only use the mobile leaderboard format if your website is optimized for mobile devices. Otherwise the viewers will most likely bounce and your ad spend on that ad will be waster.
I hope this helps.
BigTurns Professional Services Ltd
Vancouver, BC V6E 4R1