Answer

In one Jain Navgrah/Siddhachakra devotional chart, Thursday (Bruhaspati/Guruvar) is associated with Shri Adinath, Shri Ajitnath, Shri Sambhavnath, Shri Abhinandan Swami, Shri Sumatinath, Shri Suparshwanath, Shri Shitalnath, and Shri Shreyanshnath. ( storiesbyarpit.com)

Explanation

So, for Thursday, it is not just one Tirthankar in this chart, but a group of Tirthankars linked with that day. ( storiesbyarpit.com)

Takeaway

If you want, I can also give you the full weekday-wise Tirthankar list in a simple table.