Sea salt and malt vinegar. I am Canadian and it's a thing.

In Belgium: Tartare or Mayo. Andalouse for the gal, thanks

In the UK: Salt and Vinegar

In both cases: I will have to change seat if you plop yourself in front of me with your poor fries inundated by ketchup. Only the French do that, and it is a Casus Belli in my book.

Mayo

Mayo.

Maybe add some garlic, and bam:

Aioli.

Wendy's Frosty

Mayonnaise

Fry sauce (ketchup+mayo) with pickle juice. 👌

Malt vinegar 🇨🇦

Or cheese curds and gravy 🇲🇶

Salt

Mayonnaise. Fight me.

peanut sauce / satay sauce

nothing beats it

Gravy or curry sauce

Carne Asada, Cheese, Sour Cream and Guacamole

Chili and cheese

I haven't seen anyone mention nutritional yeast yet, but that's become my go-to seasoning for almost everything; popcorn, pizza, scrambled eggs, bread, ramen, soft pretzels, and of course on fries. So damn good!

(Yes, I realize the name "nutritional yeast" sounds vaguely unpleasant and unappetizing, but I promise it's incredible if you like savory flavors, and it can also be used as a cheese powder substitute in vegan recipes.)

Gravy and squeaky cheese curds

Salt and Vinegar.

Never really liked ketchup.

Mayonnaise

War

No really, that's a thing.

Basically mayo, peanut sauce and diced onions (some add ketchup or curry sauce too, but I don't like that, personally)

mustard! its always available and awesome.

Malt vinegar or brown sauce

More fries. ¯\_(ツ)_/¯

Ranch dressing powder

Mayo mixed with red curry paste

Blue cheese dressing

Where I live Zoervleis is a favorite of many. One can get it in any Snackbar.

Seasoning salt

Ranch dressing and Buffalo sauce

If it's just fries, then nothing other than salt.

Otherwise, cheese curds and gravy.

Mayo, or vinegar

Ketchup fucking sucks

Cheese and gravy (not the Canadian thing)

chili cheese!!

Barbecue sauce

Old Bay

Salt

Tarter sauce or ranch dressing.

Spicy BBQ