Baby foods that are good to start with for a 4 month old ??

Okay before I get hammered about babies shouldn’t eat before 6 months if you’re going to say that please refrain from commenting....

PEDIATRICIAN APPROVAL

At my 4 month check up the doctor recommended starting him on some baby food to help him get use to it... it’s not replacing his bottles it’s just alittle bit every night since he is starting to show more interest... we have been giving him baby cereal mixed with an ounce of formula but his doctor mentioned prunes would be a good one to try and I just feel like that might upset his tummy so I was wondering if anyone else had start their babies earlier what they have used??