import re

my_list = ['Prix TTC euros : 10,10', 'Prix HT euros 8,42', 'TVA (20.00%) euros : 1,68']

for item in my_list:
	found = re.search(r'[-+]?\b(?!\d+(?:[,.]\d+)?%)\d+(?:[.,]\d+)?', item)
	if found:
		print(found.group())