import re

pattern = r"^name: .*(?:\n(?!name: ).*)*"

lines = """name: marvin
attribute: one
day: monday
dayalt: test    << this is a field that can sometimes show up
name: judy
attribute: two
day: tuesday
name: dot
attribute: three
day: wednesday
"""

matches = re.findall(pattern, lines, re.MULTILINE)
print(matches)