Volkswagen

Honestly I fail to see any major functional differences between rounded/arrowhead/straight axe blades (unless the shaping is extreme).
 
European straight axe blades (Mostly halberds etc.) - 
 
http://sagy.vikingove.cz/wp-content/uploads/2016/07/lunow.jpg
https://s-media-cache-ak0.pinimg.com/236x/a7/0f/89/a70f89b9cbac21a2f841c2aa4cb6af6d.jpg
http://static.webshopapp.com/shops/036200/files/012036099/pole-axe-wallace-collection.jpg
http://s277.photobucket.com/user/Dstaberg/media/Weapons/swiss_extanthalb.jpg.html
https://s-media-cache-ak0.pinimg.com/236x/b7/90/ac/b790ac2d22b638a3b93c24e447133141.jpg
http://alex-bratina.narod.ru/clemmus/img/CMA_.1916.1561.jpg
http://manuscriptminiatures.com/media/manuscriptminiatures.com/original/1109-1.jpg
 
Some Indo-Persians (one from Philippines):
 
http://101antiquesword.com/image/cache/data/persian%20axe%20101-800x600.jpg
https://s-media-cache-ak0.pinimg.com/736x/55/52/2f/55522f58a0bbe87cbc7907eacba83d8c.jpg http://thumbs.picclick.com/00/s/ODAwWDc5OQ==/z/FfwAAOSwnNBXXZwN/$/Rare-Antique-Chieftains-Kalinga-Warriors-Head-Axe-Philippine-_1.jpg https://s-media-cache-ak0.pinimg.com/236x/54/3c/e3/543ce38d44d6afc09b8f5b618f31e891.jpg

Best supressor