We got a terrier pup back in jan,, for my then 3 year old lad,,, as he was scared of my other dog, a lurcher,, we got a border terrier with a bit of patt in its make up, and it's helped him big time.
Don't think you could go far wrong with most terriers or cross breads like terrier cross spaniel ect,,, just decide what you do or don't want,, I deffo don't want a dog that goes to ground,,,