What Hanzi-Latin hybrid characters exist?
If you consider only "official" characters encoded in the Unicode 12.1, as opposed to the Private Use Area (PUA) that you are referring to, or other unstandardized and humorous characters, then there doesn't seem to be any Latin-Hanzi hybrids. At all.

I carefully looked through Unicode 12.1 ranges for Chinese, Japanese, Korean, and Vietnamese characters, specifically:  


CJK Unified Ideographs Extension A
CJK Unified Ideographs Extension B – this document alone took me 3 days to process.
CJK Unified Ideographs Extension C
CJK Unified Ideographs Extension D
CJK Unified Ideographs Extension E
CJK Unified Ideographs Extension F
CJK Compatibility Ideographs
CJK Unified Ideographs


And noticed plenty of unusual and peculiar ideographs, like these:





But not a single character contains a Latin letter.

The closest to look like having a letter inside are these two. They have a stroke that looks precisely like a lowercase Greek alpha: