KY Jelly is my go-to, you can find it at pretty much any cvs or target, or here on Amazon:

https://www.amazon.com/dp/B002K4EHW6/ref=cm_sw_r_cp_api_glt_i_RJ5ZTSKKHSRE3J649DWD

This other one called “Paloqueth” from Amazon works amazing for me, and it’s way cheaper (KY jelly is $3/per ounce while this one is $1/per ounce):

https://www.amazon.com/dp/B01FR1OD04/ref=cm_sw_r_cp_api_glt_i_CPQENZP8VA1QN65K09SE

Basically you just want to look for anything water-based that is paraben free, triclosan free, and alcohol free, because those can be irritating :)