google fi is great! It's very reasonable data + voice rates everywhere, and it can do wi-fi calling + texting so you can avoid paying anything if you’re on wi-fi
T-Mobile is also good. Comes with unlimited international data roaming. It’s not the fastest speeds overseas but you can upgrade for $5 a day. If you’re ok with slower speeds when traveling, free is amazing. The plans are good too - currently paying $120 for 5 line family plan.
Depending on how much time you will be spending in a particular country you can also buy a local pay as you go SIM. You can get a US number through google voice, to still get voicemails, SMS, free calls to the US, and sometimes receives calls abroad (receiving calls is a bit sporadic). Highly recommend having a google voice number for all SMS verification challenges if you're abroad a lot.