Best counter to Lapras?

No better options. Arcanine with Fire Fang / Fire Blast is the best available "counter" to Lapras.

Arcanine is my best option as well.
I wasn't happy with Machamp, espacially because Karate Chop is such a bad attack.
I much prefer Wigglytuff with Pound. Unfortunately there is no counter that completely crashes Lapras.

My favorite counter is Machamp. I know a lot of people aren't fans of him, but I find him with cross chop to be more than effective when combined with his bulk.

Arcanine is probably best counter, and I prefer bite over fire fang. Bite is quicker with a better EPS, so it charges fire blast quicker.

Other options are bulky pokemon that do neutral damage. As mentioned, Wigglytuff is a good option, and I use my poison jab/sludge wave Muk.

Poliwrath with mud shot/submission is a good option too, but like Machamp, he lacks in damage.

I use Jolteon. His fast attacks allow me to get in a couple between each dodge. hes quick so I rarely miss a dodge. Yeah he is a glass cannon but I rarely miss a dodge with him. I use an 1800 Jolteon. Use him a bunch against Vaporeons. Also have a 1600 Electabuzz that fairs pretty well too.

I have a 1400cp electabuzz with thunder shock and thunder which I use against laprasses. My electabuzz will always win as long as I am on point with my dodges. Still not a great counter though

I use Arcanine with fire moves just like almost everyone, but in case that I have assigned Arcanine to fight another pokémon, then I use Wigglytuff (full powered up with pound and hyperbeam) against Lapras and he succesfully complete the job.

I don't have one, but I would love to try a kabutops with stone edge against lapras. I think this might be the best counter. The ideal moveset would be mud shot/stone edge.