import re
text = "Word1 content1 content1 content1\n content2 content2 content2\n content3 content3 content3\nWord2"
match = re.search(r'Word1[\s:]*((?:.+\n)*)Word2', text)
if match:
print([s.strip() for s in match.group(1).splitlines()])
aW1wb3J0IHJlCnRleHQgPSAiV29yZDEgICBjb250ZW50MSBjb250ZW50MSBjb250ZW50MVxuICAgICAgIGNvbnRlbnQyIGNvbnRlbnQyIGNvbnRlbnQyXG4gICAgICAgICAgY29udGVudDMgY29udGVudDMgY29udGVudDNcbldvcmQyIgptYXRjaCA9IHJlLnNlYXJjaChyJ1dvcmQxW1xzOl0qKCg/Oi4rXG4pKilXb3JkMicsIHRleHQpCmlmIG1hdGNoOgoJcHJpbnQoW3Muc3RyaXAoKSBmb3IgcyBpbiBtYXRjaC5ncm91cCgxKS5zcGxpdGxpbmVzKCldKQ==