import re
from bs4 import BeautifulSoup
html = """
<tr>
    <td class="m" id="b1"><a href="/QSYcfT" id="c1" target="_blank" onClick="vPI('https://www.youtube.com/watch?v=BFNH-6K10Ic', 'QSYcfT', this.id); this.blur(); return false;">TF4 - Oreos</a> <a href="#" onClick="return lkP('1', 'QSYcfT');" id="x1"><font class="bp">(0)</font></a></td>
    <td class="m" id="b2"><a href="/zXHNvp" id="c2" target="_blank" onClick="vPI('https://www.youtube.com/watch?v=0vjcGwZGBYI', 'zXHNvp', this.id); this.blur(); return false;">Awesome Game Boy Facts</a> <a href="#" onClick="return lkP('2', 'zXHNvp');" id="x2"><font class="bp">(0)</font></a></td>
</tr>
"""
soup = BeautifulSoup(html)
links = soup.find_all('a', {'id': re.compile('^c\\d+')})
for link in links:
    pass
Найдите конкретный текст ссылки с помощью bs4