Portable Charger

I have an Phone Xr and will be getting Phone 11. I am looking for a portable charger to carry with me to use with the Phone 11. I will be using an Otterbox case. I am looking for something small and reliable that I can put in my pocket, jeans or jacket to carry around to charge the phone at least to 80%. I know there is a variety of portable chargers of various sizes and options.

Thanks.