Holafly is THE best-known international eSIM provider. It advertises heavily and is relatively expensive compared to many other providers.
Holafly offers only unlimited plans that you can book for a set number of days, both for individual countries and for specific regions. With Holafly, too, you only get a certain amount of high-speed data per day before the speed drops to 1 Mbit/s. The high-speed data allowance ranges from 0.5 GB/day for certain regional plans to 2 GB for plans covering specific countries.