Schick/Edgewell also makes these. They should also be compatible.

https://www.amazon.com/dp/B07QHGR86P/ref=cm_sw_r_oth_api_i_w.tGEbHKMD3WD

https://www.walmart.com/ip/Equate-5-Blade-Disposable-Razors-for-Women-3-count/46309442

https://old.reddit.com/r/ladyshavers/comments/flqkh5/billie_razor_head_compatible/

Here is proof that the cartridges are made by Schick/Edgewell.

This Wall Street Journal article clearly states that Schick made the cartridges even before it acquired Billie.

https://www.wsj.com/articles/schick-owner-buys-womens-razor-brand-billie-for-310-million-11638222296