Your mystery houseplant appears to be the charmer, Callisia repens. There are different kinds and species, C. elegans, E. fragrans, and C.f. 'Melnickoff'. In the Commelinaceae family of plants; commonly called "Inch plant".

Care tips: Light - Give bright light with three or four hours of direct sunlight at all times of the year. Morning sunlight is fine.

Watering: During active growth (now), water well, enough to keep the potting mixture thoroughly moist, but never allow pots to sit in water that is drained into the saucer below the pot (discard water after a few minutes) water early in the day with lukewarm water or you can water at the sink and let drain.

In slow growth during the short days of winter, a rest period is best for the plant so needs to be watered sparingly, giving enough water to make the mixture barely moist, then allow the top two-thirds of the top soil to dry out between waterings, so less frequently. Check moisture in the soil with your handy fingers.

Temperature: Callisias thrive in normally warm rooms. It is advisable, however to give them a short winter rest period at 50-60 degrees F. (so not on a heater during winter, of course not too cold either).

Repotting comes later in spring after a couple of years along with taking cuttings for more plants, right, you need that, Ha! Trim faded stems if needed.
Let's see how the plant does after some exposure to required sunlight as some varieties have leafy strips, well, we shall see.

Take care and enjoy your lovely houseplant.