Are there any Christograms that were used by Early Christians but are no more in use?

Christogram (Latin: Monogramma Christi) is a monogram or combination of letters that forms an abbreviation for the name of Jesus Christ, traditionally used as a religious symbol within the Church. As of today, two Christograms namely Chi Rho (XP) and IHS are in use, the former having an artistic look and the latter, a plain look. There is however, an intertwined version of IHS seen in some ancient churches like St Martin's in Northern France. My question is: **Are there other Christograms that were used by early Christians but are no more in use?**