Aside from Lebara, are there any other sim only deals provide free international phone calls?

Hi,

My job requires me to very occasionally make phone calls to USA, Mexico, China and Hongkong. I cant get reimburse for these phone calls (or I can, but the time I have to fill in the online reimburse forms, the proofs I need to provide that the phone calls are work related, wait management to approve it, and sometimes they'll reject it for some stupid reasons etc etc… just not worth it).

I'm using O2 (I HATED it, bad reception in a lot of places), and finally my contract will end next month. I'm now looking where to switch, and found Lebara is pretty cheap and there's free international minutes!

Is Lebara good? I heard it uses the same Vodafone network so it should be OK, but in the meantime, I wonder if there's any other networks also provides free international minutes?

I tried to google but seems like all others only provides add-ons and bundles, not free. I hope you can confirm my search, that only Lebara has such free international minutes?

Thanks so much!!